Model Engine Maker

Supporting => Tooling & Machines => Topic started by: Firebird on August 26, 2013, 06:47:59 PM

Title: Building a 7" rotary table
Post by: Firebird on August 26, 2013, 06:47:59 PM
Hi

One of the best things I have done is to fit a 4 jaw independant chuck to my vertex 4" rotary table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03661_zps5182e1ba.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03661_zps5182e1ba.jpg.html)

Setting jobs up in the mill is easy and very accurate using a DTI. It's so useful that I'm reluctant to remove it when other jobs come up. What I could do with is another rotary table.

Have you seen the price of these things now  :rant: :rant:

It was a big expense when I bought mine about 6 years ago but they have about doubled in price, beyond my pocket now.

Plan B.   Can I build one  :noidea: I remembered seeing Arnold build one so I dug back and found his build and have just finished reading it, excellent Arnold  :praise2: :praise2:

I'm going to have a go at something around 7". Like Arnold I have started by throwing a few bits on the bench.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03664_zpsd6300930.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03664_zpsd6300930.jpg.html)

Some 50mm x 15mm steel bar, a gear, origin unknown but big enough to get a 7" table and thick enough to cut T slots if I wish. Some brass rings for the worm wheel, a bearing and a bit of 1/2 steel plate.

This will be one of those projects that lies on the bench and gets worked on every now and then so don't expect any rapid results  ;D ;D

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: tel on August 26, 2013, 09:08:49 PM
I'll be looking in as you progress Rich!  :ThumbsUp:
Title: Re: Building a 7" rotary table
Post by: arnoldb on August 27, 2013, 08:17:55 PM
Cheers Rich  :cheers:
It's a fun bit to build.  I use mine all the time and never regretted effort I spent on it.
I'll definitely be following along; good start  :ThumbsUp:

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Don1966 on August 30, 2013, 02:48:00 AM
You have my interest Rich, I be tagging along.

Don
Title: Re: Building a 7" rotary table
Post by: swilliams on August 30, 2013, 03:13:08 AM
You have my interest Rich, I be tagging along.

Don

Mine too

Steve
Title: Re: Building a 7" rotary table
Post by: ths on August 30, 2013, 04:48:31 AM
Me too! Hugh.
Title: Re: Building a 7" rotary table
Post by: Firebird on August 30, 2013, 10:30:37 PM
Hi

Thanks gents.

A question If I may. The rotary table I have is 90:1, ie one turn of the handle = 4°. I think Arnold opted for 72:1, ie 5° per turn and I have seen 60:1, ie 6° per turn. I can see the advantage of 90:1, a finer feed and possibly more accurate? Anybody got any thoughts on this.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Maryak on August 31, 2013, 01:06:33 AM
I can see the advantage of 90:1, a finer feed and possibly more accurate
Rich

Hi Rich,

IMHO the finer feed is the key.

90 : 1 gives the possibility of smaller increments of division using a vernier scale on the handwheel. With the correct dividing plates all worm drive ratios divide as accurately as the tolerances of construction permit.

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: Jo on August 31, 2013, 07:39:15 AM
Two of my rotary tables have 90:1 and that seems about right. The BCA is 180:1 and you spend for ever winding the handle but as she is for very fine work thats ok ;).

One feature you might like to consider is some sort of means to disengage the worm so that the table free wheels: it saves a lot of winding. And a lock to keep it in position.. and stops for either end of a cut....

Jo
Title: Re: Building a 7" rotary table
Post by: arnoldb on August 31, 2013, 12:27:00 PM
I used the 72 tooth approach for a couple of reasons:
There was only limited space for the worm wheel, and I didn't want to make the teeth on it too fine, so instead of 90 teeth at a smaller module, the 72 let me use a bigger module, which made it easier to mesh things up reliably.
It's easier to work with 5o increments on the dials; no need to keep track of where the last position was and count divisions; I can just read off the current position.
Anybody going through the build log (http://madmodder.net/index.php/topic,7488.msg80306.html#msg80306) will see that I made a bit of a stuff-up with the vernier scale - so instead of 0.001o accuracy I was left with 0.01o accuracy.  I've found this to be more than adequate in practical use.

As I mostly use it for small parts, when milling curves and so on the feed rate matches well with good control, though I have found the feed a bit course when going over a 50mm radius - at that point the finer feed afforded by a 90 tooth gear would be nice.

The zero-able handwheel is a pleasure to use, as is the eccentric adjustment to remove backlash; in fact, properly adjusted there is pretty much zero backlash on it.
In retrospect, one thing that I would like to add to the table is an adjustable degree ring instead of the fixed markings that I used.  This would be very handy when I use the screw-on chuck adapter to transfer workpieces already mounted in chucks between the lathe and RT.

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Firebird on August 31, 2013, 01:35:32 PM
Hi

Thanks for the info. I figured 90:1 would be best. I may have a practice at cutting the worm wheel on some scrap ally. I have some old largish whitworth taps that I will dig out and see what they cut like. If thats ok I can then work out what size worm blank I will need for 90 teeth.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: mklotz on August 31, 2013, 05:20:45 PM
The BCA is 180:1 and you spend for ever winding the handle but as she is for very fine work thats ok ;).

Mine is a 90:1 as well and, as Jo points out, winding that handle over any significant angular distance can be tiring and tedious.

In your design consider arranging for some sort of fitting at the outboard end of the handle shaft so you can mechanically "plug in" a common battery-operated power screwdriver. 
Title: Re: Building a 7" rotary table
Post by: Firebird on August 31, 2013, 08:38:16 PM
Hi

Marv, I have been out playing this afternoon and the same idea occured to me. I'm looking into taking the shaft right through and out the back with the possibility of fitting a stepper motor.

I had a practice run with a couple of worm gears. The first one I used a 1/2" Whitworth tap which is 12 threads to the inch. First job was to turn a blank from some scrap ally.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03667_zps8f0e3e95.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03667_zps8f0e3e95.jpg.html)

This is the setup I cobbled together. I just messed about with various spacers until I got the blank on centre height.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03675_zps0fe20404.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03675_zps0fe20404.jpg.html)

The blank spins freely and is not held on. The downward cutting force keeps it on. Sorry there are no more photos of the first attempt. You can see I didn't quite get centre height but not bad though.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03687_zps41557a15.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03687_zps41557a15.jpg.html)

My second attempt I used a 5/8" Whitworth tap which is 11 threads to the inch, slightly coarser. Again I just messed about with various spacers until centre height was attained. alitlle more accurately this time.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03677_zps00e84095.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03677_zps00e84095.jpg.html)

Not too bad at all.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03679_zps26c7200c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03679_zps26c7200c.jpg.html)

And compared to the first attempt.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03688_zpsfbc76afd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03688_zpsfbc76afd.jpg.html)

A bit of video, not very good I'm afraid but you get the idea.

f79QUrznS7k
To calculate the blank size I used this formulae.

Thread pitch x number of teeth divided by 3.142

For the 1/2" whitworth tap with 12 tpi

0.0833 X 90  ÷ 3.142  = 2.3870"

For the 5/8" whitworth tap which is 11 tpi

0.0909  X  90  ÷ 3.142  =  2.6040"

I have a 3/4" whitworth tap which is 10 tpi that I am going to try.

0.1  X  90  ÷  3.142  =  2.8644"

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on September 01, 2013, 02:10:43 PM
Hi

This morning I finished the experiment by cutting a 90 tooth worm wheel with a 3/4" whitworth 10 tpi tap.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03696_zps507112ea.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03696_zps507112ea.jpg.html)

Compared to the 11 tpi and the 12 tpi

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03702_zps92ce0115.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03702_zps92ce0115.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03699_zps92fd738a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03699_zps92fd738a.jpg.html)

This is me trying the worm wheel on the cross slide lead screw of my Myford which is 10 tpi. it rolls along nicely.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03705_zpsacaaccd1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03705_zpsacaaccd1.jpg.html)

A bit of video of the cutting

H-vL93ObVY0
I think the 10 tpi is the one I will go for, it looks right. The tap I have used is not ideal. one tooth has a chip out of it and is a taper tap. I'll see if I can beg or borrow a better one.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on September 01, 2013, 08:27:57 PM
Hi

another question if i may. Just read Arnolds build again and he gashed the blank with a slitting saw prior to cutting the teeth. He held the blank at an angle of 4.5°. Iv'e looked but can't find the angle of 3/4" 10tpi whitworth, anybody know what it is?

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Maryak on September 02, 2013, 12:58:51 AM
Hi Rich,

Let helix angle = A

Tan A = Pitch/(EffectiveDiaxPI)

Tan A = 0.1/(0.686xPI)

A = 2.650

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: SandCam on September 02, 2013, 02:36:51 PM
Hi Rich and Bob,

No... I have not left this world yet :old:... just been busy on other things in life.
 
Bob... How are things doing down under? Hope you and yours are keeping well.


The helix angle you have calculated is certainly correct, however, it may not be clear to some viewers, whom may not be so well versed in trig, exactly how you arrived at it...

If I may be permitted to elaborate a little on your posted formula…

Let helix angle = A

A = arctangent (Tan A)

Tan A = Pitch/(Effective Dia x PI)

Tan A = 0.1/(0.686xPI)

Tan A = 0.0464

A = arctangent (0.0464)

A = 2.650

NOTE… on a calculator the arctangent key is usually marked as   tan-1

The Effective Dia is found from OD – (0.64 x pitch) for a Whitworth thread form.

In the case of the Whitworth thread form this is also the PITCH DIA.

Hope this clears up any possible confussion.


Which brings me to my next point…

Rich… I don't recall seeing one of these on your Portable Engine >:D :lolb:

The formula you used for the OD of your blank

OD = (Number of teeth x pitch) / Pi

This will give you the PITCH DIA… not the true OD
For Whitworth thread form… you need to add the thread depth to this to obtain the true OD

Thread depth for a Whitworth thread being (0.64 x pitch)… in your case this will be 0.064”.

If you use OD= ((number of teeth + 2) x pitch) / Pi
This will give you a very close approximation.

If you use the pitch dia for your OD... then you can only cut to a depth of 0.032” before you begin to damage the thread form by thinning it too much… you also run the risk of reducing the actual number of teeth by cutting beyond this depth.

Have you counted the actual number of teeth on your last finished worm wheel?

Hope this helps a bit and does not add to any confussion.

Keep happy. ;D

Best regards.

Sandy  :cheers:

Title: Re: Building a 7" rotary table
Post by: mklotz on September 02, 2013, 05:02:01 PM
Quote
Tan A = 0.0464º
A = arctangent (0.0464º)

A minor nit, Sandy.  The tangent is equal to a unitless, i.e. no degrees, number.  When you take the arctangent, the result is an angle, A, which you express with the degree symbol. 
Title: Re: Building a 7" rotary table
Post by: SandCam on September 02, 2013, 05:51:07 PM
OOPS!!!

You are quite correct Marv... my error... sorry... I will get back in the corner and write 100 lines.
Original post edited to remove error.

Best regards.

Sandy
Title: Re: Building a 7" rotary table
Post by: Firebird on September 02, 2013, 09:47:59 PM
Hi Bob Sandy & Marv

Erm tangent helix arctangent :shrug: tan A pitch  :headscratch:  :noidea: :noidea:  :help:

You all lost me after the first line  :embarassed:

But I now know its 2.65°  :cheers: :ThumbsUp: :whoohoo:

Now Sandy lets move on to the diametre of the blank I need.

If you use OD= ((number of teeth + 2) x pitch) / Pi
This will give you a very close approximation.

90 + 2  X  .1  ÷  3.1428  =  2.9273   :thinking:

Why do I have to add 2  :noidea:

I haven't counted the actual number of teeth, never thought to do that  :facepalm:

Thankyou all for patience.

Cheers

Rich   


Title: Re: Building a 7" rotary table
Post by: SandCam on September 02, 2013, 10:59:51 PM
Hi Rich,

I thought that lot would get you going  :mischief: :naughty:

In your original calculation you had...

OD = 90 x 0.1 / pi which gave you 2.864"

This would be the Pitch dia of the gear wheel... for WHITWORTH threads this would be the diameter at half the thread height... therefore, you need to add the other half to both sides of the circle.

You do this, for WHITWORTH thread form by adding the thread depth to the PITCH dia... this takes care of both sides of the circle.

For WHITWORTH threads the thread depth is calculated as follows: -

Depth = 0.64 x pitch... = 0.64 x 0.1... = 0.064"

The true OD would thus be 2.864 + 0.064 = 2.928"

The OD for a spur gear is... 

OD = ((N+2) x pitch) / pi... where N is the number of teeth required.

So ((90 + 2) x 0.1) / pi ... = 9.2/pi... = 2.928"

So.. by adding 2 to the tooth count the calculation takes care of adding the tooth depth for you.

 You would still need to find, or calculate, the tooth depth though... so you know how deep to cut.

Strictly speaking, there is still a small error using either method since both of the above methods are for STRAIGHT cut spur gear teeth.

A worm wheel has helical cut teeth and therefore the PITCH of the teeth is increased, over that of a corresponding spur gear,  due to the angle... which in turn increases the OD... but for this excercise the above calcs will be adequate... unless you want to get into Cosines as well as all the others :censored:

I hope this all makes sense.

Keep happy.

Sandy. :cheers:
Title: Re: Building a 7" rotary table
Post by: Maryak on September 03, 2013, 01:12:30 AM
Hi Rich,

Bloody gears.........one more thing and that is the width of the wheel blank.

Axial width = (2.38 x Pitch) + 0.25

                 = (2.38 x 0.1")+0.25

                 = 0.488"

Hope this helps

Best Regards
Bob

PS Hi Sandy, The spring is on us in down underland after a very wet winter. And I have no objections to your expanding the formula. It's good somebody looks over my shoulder, preferably with a can of WD 40 at the ready to loosen up my gears.
Title: Re: Building a 7" rotary table
Post by: Pete49 on September 03, 2013, 04:03:20 AM
thanks for bringing this up again Rich. I saw this type being made recently and never gave it much thought but as you was making a bigger RT I was thinking (yep bad move :Lol:) I wonder if its as easy as it looks :headscratch: Anyhoo I found a piece of scrap ali and a 1/2" BSW tap and had at it ...wow it is as easy as it looks and I started on another round of dangerous thinking until Bob Marv and Sandy got involved and now my head is in a real spin. Damn those maths experts messing up my mind  :Jester: The main thing is you got me to try an idea and it worked so now its filed away and maybe used at a later date
Pete
Title: Re: Building a 7" rotary table
Post by: Maryak on September 03, 2013, 04:19:22 AM
Hi Guys,

I took the liberty of running this through my CAD and worm spreadsheet which I have attached.


(http://i389.photobucket.com/albums/oo340/Maryak/FbirdW_zps81b02f14.jpg)

Oh and Pete in my case when it comes to maths:

Expert =  X,spurt................X, (the unknown factor) and spurt............a drip under pressure.

As Sandy alluded to; there are some minor differences between actual worm calculations and those using a tap as the hob. e.g. helix angles. In a practical sense the gashing angle does not have to be all that accurate just good enough and with the correct number of teeth to give the tap a reasonable start.

I hope it's of some use.

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: Pete49 on September 03, 2013, 01:54:18 PM
Just to clear up a slight error in my post ....my expression of expert was not as yours Bob more a complimentary version as in extremely clever. But you knew that....I hope :Doh:
Pete
Title: Re: Building a 7" rotary table
Post by: mklotz on September 03, 2013, 05:04:12 PM
Just to clear up a slight error in my post ....my expression of expert was not as yours Bob more a complimentary version as in extremely clever. But you knew that....I hope
Pete

Thanks for making that clear, Pete.
Title: Re: Building a 7" rotary table
Post by: Tennessee Whiskey on September 03, 2013, 08:58:12 PM
Y'all have been around y'alls wives way too much. I had to reread it three times to even have a clue why Pete was apologizing. Glad y'all got that one worked out.

Whiskey
Title: Re: Building a 7" rotary table
Post by: Firebird on September 03, 2013, 09:16:20 PM
Hi

Wonderful stuff gentlemen, thankyou very much  :praise2:

I got a 3/4" 10tpi spiral flute tap today, I'll get a photo posted soon. It may work without gashing the blank, I'll give it a go next time I get out in the shop.

Pete the xspurt tag I could wear easily  :lolb:

Bob, if I can cut a gear as good as your drawing I will be a happy man, and thanks for gear blank width formulae.

Sandy, cosines  :facepalm2: now why didn't I think of those

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Maryak on September 03, 2013, 10:49:38 PM

Bob, if I can cut a gear as good as your drawing I will be a happy man


Me too, the real world is far more demanding than cyberspace but it does give an idea of what things should look like.

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: SandCam on September 03, 2013, 11:33:34 PM
Hi Guy's,

OK then... I have finished writing my 100 lines.

" the tangent is = to a unitless number...PROOF READ before posting" :hammerbash:

Thanks for picking that up Marv. :praise2: :NotWorthy:


Rich... You are welcome... we are always happy to help where we can.

I think you will find the spiral tap will work a lot better as it will maintain the drive to the blank more consistently... the straight flute tap can lose drive if the cutting tooth exits before the next one makes contact... resulting in a more intermittent drive.

Pete... I don't believe I would even qualify for the xspurt tag when it comes to maths... I like to think I know/remember just enough to get me into trouble... but thanks for the complement... and sorry for the head spin... that was not intended.

Bob... I hope you have a better spring than we had this year... ours was cold and wet until late May.

Keep Happy guy's.

Best regards.

Sandy. :cheers:

Title: Re: Building a 7" rotary table
Post by: Lew Hartswick on September 04, 2013, 01:57:54 PM
< Expert =  X,spurt................X, (the unknown factor) and spurt............a drip under pressure.>
 OR. Ex as in "former" or "has been" , which results in:
A "Has been, drip under pressure".  The way I heard it.
   ...lew...
Title: Re: Building a 7" rotary table
Post by: Firebird on September 07, 2013, 04:44:55 PM
Hi

Some success and some failure today.

I made a mandril to hold the big gear that I intended to use as the table. It just fits in the lathe.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03706_zps18006fa7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03706_zps18006fa7.jpg.html)

Unfortunately when I tried to machine it I found that the gear must be hardened. I trashed 2 TC tips and had to give up. I will have to source another piece from somewhere.

Then I set up to cut another worm wheel using the helical tap.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03711_zpsc83a57a7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03711_zpsc83a57a7.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03713_zpsd66e24a3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03713_zpsd66e24a3.jpg.html)

A video of the cutting

ZHmSvreRHvE
Not bad at all

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03717_zpsa0dd43b4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03717_zpsa0dd43b4.jpg.html)

It looks good and the helical tap cuts easily and turns the blank without gashing.

But I have a problem, its got 94 teeth  :facepalm2:

Where oh where have I gone wrong  :help:

I machined the blank to

So ((90 + 2) x 0.1) / pi ... = 9.2/pi... = 2.928"

Heeeeeeeeeeeeeeeeeeeeeeeelp

Cheers

Rich



Title: Re: Building a 7" rotary table
Post by: Don1966 on September 07, 2013, 05:05:02 PM
Rich in that formula is the .1 the circular pitch or the thread pitch. You need the circular pitch here.
Or you could use (constant .3183*TPI*number of teeth) * (2+ depth of teeth).
I may be wrong here since I am pretty new to all this.

Don
Title: Re: Building a 7" rotary table
Post by: Brian Rupnow on September 07, 2013, 11:10:38 PM
Very interesting stuff indeed. Math aside, I had no idea that a gear of this type could be made this way. I had never actually thought about this type of thing being built in a small "home" machine shop. Thank you for the education.--Brian
Title: Re: Building a 7" rotary table
Post by: SandCam on September 08, 2013, 12:05:42 AM
Hi Rich,

You need to gash the blank or the tap will revert to cutting teeth at 0.1" pitch on the periphery... which would result in 92 teeth.
Add in any slip and you could well end up with more.

When you have gashed the blank... bring the blank up to the tap (with the lathe stopped)and make sure the closest tooth lines up with a gash then add about 0.01" feed depth... then turn on the lathe... allow the work to rotate at least 3 to 4 complete turns, to allow the cutter to even out the pitch differences, before increasing the feed depth by another 0.01"... repeat this until you get almost to final depth, say 0.060", then do your final pass with the final 0.004" cut.

Hi Brian,

Good to see you have found us over here... and who has been a busy boy with all those lovely new engines  :ThumbsUp:.


Keep happy.

Best regards.

Sandy.

PS... make sure you get the gash angle sloping in the correct direction or all sorts of strange things will happen :naughty:
Title: Re: Building a 7" rotary table
Post by: Pete49 on September 08, 2013, 09:14:21 AM
Oh no more stuff to learn. The only gashing I know of results in my blood loss.  :lolb: Can you explain further?
Pete
Title: Re: Building a 7" rotary table
Post by: Noitoen on September 08, 2013, 01:10:48 PM
 :noidea: Instead of "pushing" the blank sideways into the tap, if the cutting could be approached "I can't find the right words" like it was entering a hole "tangentially??" with the depth of cut already set, maybe it would work better. The tailstock centre should be thinner and the blank would move gradually to the left, until it reached the correct depth of cut, i.e. the centre of the tap.

I could draw a "crap-o-cad" to explain  ;)
Title: Re: Building a 7" rotary table
Post by: Maryak on September 08, 2013, 01:24:08 PM
Hi Pete,

Gashing means exactly what you said only in this instance it's metal removal rather than skin.

e.g.

Take the gear blank on a mandrel and mount it centrally on the rotary table /dividing head which is mounted vertically on the mill table.

Now angle the rotary table away from the vertical to a close approximation of the helix angle and ensuring the angle is of the correct hand to match the worm, (tap).

Lastly fit a slitting saw whose thickness is less than the width of the worm at the bottom and make a cut which should be deeper than the mean depth of the worm thread but not to full depth.

Rotate the blank to the next tooth and so on until all the teeth have been pre-cut so to speak.

This guides the Hob/Tap and helps prevent slip. It also ensures that the pitch is not cut on the periphery of the blank. Lastly it ensures contact by more than one tooth of the hob/tap.

Hope this helps

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: Don1966 on September 08, 2013, 03:00:45 PM
I am having trouble understanding how you can get more teeth on the gear when you have only a given circumference. If the calculation are correct, you can only place so many teeth on the gear. Since i am still learning here, can some one explain to me how you do that? Confused in Louisiana.

Don
Title: Re: Building a 7" rotary table
Post by: Firebird on September 08, 2013, 03:10:40 PM
Hi

Thanks everyone, all good advise  :ThumbsUp:

The wife went to work then keep fit for a couple of hours this morning not wanting to miss this golden opportunity I made a dash to the workshop.

First job was to machine another blank to size then figure out how to hold it at the required angle. I have a cheapo tilting vise, its actually very good value for money, not a precision vise but quite solidly made. My 4" rotary table fits in the jaws ok. In the next shot I'm using a DTI to centre the work piece in the 4 jaw chuck.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03721_zps1fb0b04e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03721_zps1fb0b04e.jpg.html)

Then using a digital angle guage set at zero.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03726_zpsde1d06fd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03726_zpsde1d06fd.jpg.html)

The table is then tilted to 2.65°. The angle guage only works to 1 decimal point so I had to feel my way between 2.6° and 2.7° but it should be near enough.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03724_zps1c29c6ad.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03724_zps1c29c6ad.jpg.html)

I have used a 1/64 slitting saw, all my others are 3/64 and 1/8 upwards too big.

Lineing up the slitting saw on centre

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03727_zpsd3c783fd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03727_zpsd3c783fd.jpg.html)

And after cutting 90 teeth

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03732_zpsf3dd8fe3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03732_zpsf3dd8fe3.jpg.html)

I have cut to a depth of .040

A bit of video, slightly wobbly and out of focus.

DoUFDOcC1U8
At this point I had to pack in before the good lady came home. I hope to get the now gashed blank back in the lathe one night this week.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on September 08, 2013, 03:19:28 PM
Hi Don

You would think it would work wouldn't you but strange things happen :noidea:

I think Sandy has explained the reason why. I'm new to this method of cutting a worm wheel as well so its all a bit experimental at the moment.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: SandCam on September 08, 2013, 05:28:30 PM
 ;D

Hi Guy's,

Good fun this, is it not!!! :naughty: :LittleDevil:

Pete,

I think BOB has answered you question as well as I could... only thing I would add would be that you gash the blank for the actual number of teeth you want on the final wormwheel... not the added +2 teeth value used for the calculation of the OD.

Rich,

Looks good now you have gashed it so hopefully this will solve the pitch/number of teeth problem.

Don,

Yes it can be a bit confusing... the pitch of the teeth on a gear is usually specified at a diameter approx 1/2 way down the tooth and is usually referred to as the PITCH DIA.
The actual tooth spacing is specified as the distance between 2 sequential teeth as measured at the PITCH DIA... this is the CIRCULAR PITCH.

To get 90 teeth at a given pitch (0.1" in Rich's case) the PITCH DIA  would need to be 90 x 0.1/pi which equals 2.864" dia, the circumference of which would be exactly divisible by 0.1"... however since this is at 1/2 tooth depth it is necessary to add on the extra for the other 1/2 tooth depth.
This is done by changing the calculation to ((Number of teeth +2) x pitch) / pi... which now gives the correct OD for the wheel... this, however, increases the circumference by 2 tooth pitches.

If you were to cut the gear using a standard gear cutter using a rotary table or dividing head then you would have no problem.
If you were cutting the gear using a hob, again no problem, providing that the workpiece was being DRIVEN at the correct rotational rate for the number of teeth required.

However, if you were trying to cut the gear with a hob using the free wheeling method... as in this case (Rich is just using a 10tpi tap as a hob) this now presents the problem of the circumference being to large and the cutting teeth will attempt to cut 0.1 pitch spacing as soon as it touches the blank... clearly this will now be the 92 teeth you calculated with.


Also, since the method can cause rotational speed variations on the blank, due to cutter drag or 2 or more teeth cutting at the same time... then the actual number of resulting teeth can be somewhat unpredictable... this would be more pronounced if using a straight fluted tap since it is possible that no teeth would be actually cutting (in the flutes of the tap) resulting in NO ROTATION of the blank.

In addition, you are also now cutting a helical tooth form which has the effect of increasing the circular pitch a little from that of a straight cut spur gear so the length of cut increases and the cutter thrust is not at right angles to the work.

Gashing the blank with the required number of teeth spaces, at the approx helix angle, encourages the tap/hob to follow the gashes, since there would be much less cutting force involved... and cutting tools tend to follow the path of least resistance... A bit like us humans :Lol:

It is a crude, but effective, method of cutting a wormwheel but without access to expensive DRIVEN HOBBING equipment it can be a usefull one... unless MORE ABSOLUTE PRECISION is required... in which case... buy a purpose made item.

I hope this helps a bit :LittleDevil:

Keep happy.

Best regards.

Sandy :cheers:
Title: Re: Building a 7" rotary table
Post by: Firebird on September 08, 2013, 06:18:35 PM
Hi

Yes its all starting to make sense now Sandy, thanks for your patience (it takes a while for things to sink into this old brain  :old: :hammerbash:)

Thanks for input Bob.

Noitoen, yes please lets see your idea.


The timing belt gears that I mastered cutting have been a real asset. I can now cut a couple of gears from start to finish in less than an hour. Iv'e used them on all sorts of projects including power drives on my mill and lathe.

If I can ,master the worm and wheel (I see the worm and wheel as the most complicated part) then I can see myself knocking up more rotary tables and dividing heads for future projects
Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Noitoen on September 08, 2013, 06:56:03 PM
Ok, let's see if you understand what I mean. If the blank, with the correct diameter is positioned like in the drawing, vertical centre aligned with the beginning of the tap and the distance to the horizontal centre at the final depth setting, by moving the blank to the left slowly, allowing the tap to cut all around, I would think that the teeth would be cut to the correct size.
Title: Re: Building a 7" rotary table
Post by: Firebird on September 08, 2013, 07:34:58 PM
Hi

Good idea Noitoen, it might work.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Pete49 on September 09, 2013, 06:36:41 AM
Thanks Bob and Sandy now I have an understanding of how it works. Just shows you can teach an old dog new tricks.  :ThumbsUp:
Pete
Title: Re: Building a 7" rotary table
Post by: Firebird on September 09, 2013, 08:47:28 PM
Hi

Be eck I think Iv'e got it  :cartwheel: :whoohoo:

The gashed blank set up in the lathe

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03736_zpsd559c31d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03736_zpsd559c31d.jpg.html)

I advanced the cross slide until I could feel the teeth of the tap mesh then with the belt tension off I turned the chuck by hand for a full revolution. Everthing seemed ok so with the lathe on its slowest belt speed and the variable speed turned down to a crawl I watched the gear slowly turn, all was well. I advanced the crosslide until a full depth cut was reached.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03745_zps9216958d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03745_zps9216958d.jpg.html)

Looks good to me and its got 90 teeth :whoohoo:

The ally blanks I have been using for practice are not quite thick enough at .4" the brass one will be .488"(thanks Bob)

My thanks to all who have helped me "master" this technique :cheers:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: SandCam on September 09, 2013, 09:43:00 PM
 ;D :ThumbsUp: :bandrock:

Well done Rich... that looks just the ticket.

When you have done your final one (Brass... or better still...BRONZE) and also the worm to go with it... I would suggest that you gently lap the two together with a small amount of metal polish (solvol autosol or some such) this will help get them bedded together and reduce any periodic error (variance in pitch and/or eccentricity around the wheel/worm... yes there will be some).

This will then help you to get a much closer fit between the two parts in your rotary table (less backlash).

Anyway.. for now many congratulations in getting the hard part sorted.

Keep happy.

Sandy. :cheers:

Title: Re: Building a 7" rotary table
Post by: Don1966 on September 10, 2013, 01:39:07 AM
Nicely done Rich, and thanks very much Sandy for taking the time and giving an explanation , it makes a lot more since to me now. 

Don
Title: Re: Building a 7" rotary table
Post by: Maryak on September 10, 2013, 03:55:26 AM
Eh by gum tha's dun it proud.  :NotWorthy:

Beyond that, 5 bals for tenacity.  :NotWorthy:

Ain't it great to see a plan come together?

Best Regards
Bob
Title: Re: Building a 7" rotary table
Post by: swilliams on September 10, 2013, 09:27:01 AM
Very nice Rich

Looks just the ticket

Steve
Title: Re: Building a 7" rotary table
Post by: Arbalest on September 10, 2013, 10:20:54 AM
Looking good Rich!
Title: Re: Building a 7" rotary table
Post by: Firebird on September 10, 2013, 09:57:51 PM
Hi

Thanks gents.

Its got to brass Sandy, partly because thats what I have and secondly have you seen the price of bronze  :rant: :rant: I don,t think I will be over working the table so brass will have todo. Anyway I can always make a new one if it wears out :Lol:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on September 10, 2013, 10:18:03 PM
Hi

My mate Julian came to the rescue with a bit of steel for the table. He has a 7" billet and said you can chop an 1" off the end of that if want. A bit of a challenge for the old bandsaw.

I held my pillar drill vise in the bandsaw vise and then held the billet in that. Using a digital angle guage on the bandsaw bed and set to zero.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03752_zpsf27449a6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03752_zpsf27449a6.jpg.html)

Then moved to the billet. Thats as near to 90° as I could get it.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03754_zps52704532.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03754_zps52704532.jpg.html)

All set up and ready to go.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03757_zpse2b282c7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03757_zpse2b282c7.jpg.html)

After about half an hour.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03758_zps37c9d175.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03758_zps37c9d175.jpg.html)

I had to leave it there, I'll finish it over the next few nights. There was a time when I would have set to with a hacksaw but those days are long gone thankfully :Lol:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: arnoldb on September 13, 2013, 05:34:05 PM
The gear came out great Rich  :ThumbsUp:

Poor bandsaw; us hobbyists do tend to push them to their limits sometimes, don't we  :Lol:

It's interesting to see that the brass is cheaper than bronze over there...  Locally I've found that phosphor bronze is cheaper than brass by weight  :headscratch: .
You could of course go for a section of hollow bronze and press an aluminium or steel core into it; might just tip the financial scales to make it cheaper or for about the same price as with the brass, and still get the slightly better wearing properties of the bronze...

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Firebird on September 13, 2013, 10:32:02 PM
Hi Arnold

You really can't knock these bandsaws can you. Tonight I finished the cut, I'll post some pictures later. I did have a problem last night in that the slot must have tightened up and pinched the bandsaw blade which snapped at the welded joint. A quick google led me to several examples of people silver soldering the joint so I gave it a go and soon had the blade running again, easier than I thought. I'm now looking into buying a roll of bandsaw blade and making my own, much cheaper. As for the bronze I'm keeping an eye on ebay but much too expensive at the moment, something might turn up though you never know.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on September 14, 2013, 05:29:50 PM
Hi

The old bandsaw finished cutting the table today.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03761_zpseebfe679.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03761_zpseebfe679.jpg.html)

I then cut 4 pieces of steel roughly to size.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03766_zps347852e4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03766_zps347852e4.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03762_zpsd7ce4f80.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03762_zpsd7ce4f80.jpg.html)

Machining the steel to size in pairs.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03771_zps3cff016b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03771_zps3cff016b.jpg.html)

Then cut the piece of 1/2" steel plate roughly to size.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03768_zps659d7b0b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03768_zps659d7b0b.jpg.html)
Cheers

Rich
 
Title: Re: Building a 7&quot; rotary table
Post by: NickG on September 14, 2013, 07:13:35 PM
Nice work Rich, thanks for that explanation Sandy. Are you sure it's got 90 teeth Rich? I counted 91 ;-)
Title: Re: Building a 7" rotary table
Post by: Firebird on September 14, 2013, 07:34:05 PM
Hi Nick

I had to go out and count them again just make sure

Yeah I'm sure its 90  :lolb:

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: NickG on September 15, 2013, 08:17:53 AM
Haha, it's great that. Does it have to be a spiral fluted tap? Also, is it possible to do it without the gashing (is it gashing, sure saw someone else saying gnashing?!) Did Sandy say if you feed it into a certain depth without letting it rotate then let it start rotating it would end up with the right no. of teeth?
Title: Re: Building a 7" rotary table
Post by: steamer on September 15, 2013, 11:05:49 AM
Haha, it's great that. Does it have to be a spiral fluted tap? Also, is it possible to do it without the gashing (is it gashing, sure saw someone else saying gnashing?!) Did Sandy say if you feed it into a certain depth without letting it rotate then let it start rotating it would end up with the right no. of teeth?

That would have been me Nick.....and I can spell to save my life...so don't follow my lead! :lolb:

Dave
Title: Re: Building a 7" rotary table
Post by: steamer on September 15, 2013, 11:12:11 AM
Rick,

Great job on the Rotab!....
Watch the EBAY prices on metals....I did a fairly exhaustive search yesterday for a piece of brass bar ( 1 x 2 x 12) and ONLINEMETALS,com had much better pricing...even with shipping!

Dave
Title: Re: Building a 7" rotary table
Post by: crankshafter on September 15, 2013, 01:15:56 PM
Hi rick
I have a pice of bronz (actualy several) but posting here from Norway would have been to expensive, sorry..
Nice work so far BTW.
CS
Title: Re: Building a 7" rotary table
Post by: SandCam on September 15, 2013, 02:04:41 PM
Hi Guy's,

Nick,

It is the gashing that dictates the number of teeth.

The bit about feeding prior to starting (Lathe STOPPED) is to ensure the TAP begins cutting in the gaps... not on top of the resulting stubs.

Feed the closest tap tooth to the wheel OD into the gash by around 0.005" - 0.010" then start the lathe... keep the lathe speed LOW and let the blank rotate at least 2 full rotations before increasing the feed depth by around 0.010" - 0.015" at a time... allow time for the blank to fully rotate around 2 full turns... repeat until around 0.005" from full depth then do the final run at 0.005" increase in depth... this will produce a better finish.

Rich... looks good so far... PS... you need a bigger bandsaw :ROFL: :Jester:

Keep happy.

Best regards.

Sandy  :cheers:
Title: Re: Building a 7&quot; rotary table
Post by: NickG on September 15, 2013, 02:30:14 PM
Lol Dave! Thanks Sandy, I see what you mean, I guess it'd have to be full depth cut to get the right pitch which would be far too much for the tap.
Title: Re: Building a 7" rotary table
Post by: Firebird on September 15, 2013, 04:54:56 PM
Hi

Thanks Guys.

Nick I think Sandy has kindly explained everthing better than I could.

I'll keep looking for some bronze. I have moved on to making the box and fitting the top plate. Once thats done I can work out where things are going. After this week I will be away from the shop for about 3 weeks so there will be time to try and source a bit of bronze.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on October 13, 2013, 04:19:18 PM
Hi

well its been a while since I last posted, we have just been on holiday in the USA but now its back to reallity. Anyway a little shop time today so some progress has been made.

I am going to the model engineering show at Warwick next weekend where I will try to pick up a bit of bronze for the worm wheel so that bit has been pushed to the back of the bench for a while.

I have machined the 4 sides to length in pairs.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03772_zps0874200f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03772_zps0874200f.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03774_zps445ee647.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03774_zps445ee647.jpg.html)

Then machined one side on all 4 at once.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03783_zpsc89471c3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03783_zpsc89471c3.jpg.html)

The cutter I am using here I only bought yesterday from arceurotrade (usual disclaimer) and is really good, I'm pleased with it. Its 1 3/4".

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03782_zpsd6344ab0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03782_zpsd6344ab0.jpg.html)

Then machined one side of the top plate. The 2 posts I am using here are car piston gudgeon pins, they make excellent stops.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03793_zpsc47d68a1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03793_zpsc47d68a1.jpg.html)

Then check that my set up is good before i machine the other 3 sides.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03795_zps9de27ca2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03795_zps9de27ca2.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03799_zpsed56824c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03799_zpsed56824c.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03801_zps9dbad9cf.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03801_zps9dbad9cf.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03804_zps0796beed.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03804_zps0796beed.jpg.html)

Cheers

Rich

Title: Re: Building a 7" rotary table
Post by: smfr on October 13, 2013, 05:18:29 PM
Looks like good progress. Those are some large lumps of metal  :Lol:

Have you given a thought to keeping the overall height down? At least on my machinery, headroom is often an issue, and a half-inch can make the difference between fitting a part in and not.

Simon
Title: Re: Building a 7" rotary table
Post by: Firebird on October 13, 2013, 07:41:01 PM
Hi Simon

The table will be used on my X3 mill which has a reasonable height. Overall height should end up about the same as my vertex 4" rotary table. The bottom of the side pieces has to be machined yet but I'll leave that for now. When the bearing and worm gear are in I'll see how much I can skim off.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on October 19, 2013, 10:16:14 PM
Hi

A question for you my learned friends

We went to the model engineering exhibition at Warwick today where I hoped to source a bit of bronze for the worm wheel. The only suitable piece I could find would have been big enough to make 3 gears but at £32.00 I couldn't justify it. I did notice though that the bronze on offer from several vendors looked very much like brass to me, a yellow colour. I have some bronze bar that has a disitinctly rosy colour. If you take a look at the 2nd picture on page 1 of this topic you will see the bits of hollow bar that I thought were brass but now I'm not so sure. The smaller diameter bit which unfortunately is just under the size I need has some distinct black marks around the outside which I understand is a feature of bronze. The 2 larger bits which are a suitable size have already been machined on the outside so no marks are visible.

How can I tell if it is bronze or brass  :headscratch:

Cheers

Rich

 
Title: Re: Building a 7" rotary table
Post by: Brian Rupnow on October 19, 2013, 11:56:11 PM
Machine it in your lathe. If it is brass, you will pull a chip similar to aluminum. If its bronze, you will be bombarded by a fine very hot powder.
Title: Re: Building a 7" rotary table
Post by: swilliams on October 20, 2013, 12:29:35 AM
Bronze is a very unspecific term, it includes a large range of possible materials, some of which are very close to brass.  It can be very hard to tell the difference between the two and just saying something is bronze doesn't mean much anyway. If it's hard brass and you keep the worm wheel lubricated it should be fine.

BTW - Hard free cutting brass will make a shower of small chips.

just my 2c
Steve
Title: Re: Building a 7" rotary table
Post by: Firebird on October 21, 2013, 09:10:36 PM
Thanks Brian and Steve.

I'll try machining it and see what happens

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: arnoldb on October 22, 2013, 06:44:10 PM
Hi Rich.

Yes, the distinction is very difficult...  In the photo below (click for a larger image) is a bit of "hard brass" rod on the left and two pieces of phosphor bronze on the right:
(http://www.nam-engineering.com/cm/albums/userpics/10004/normal_IMG_5418.JPG) (http://www.nam-engineering.com/cm/displayimage.php?pid=8704&fullsize=1)

I brightened up the end of the brass bar and the top bit of PB with some Scotch-brite to get rid of the patina to show the raw colour - which is nearly identical.  The PB looks just a tiny bit more coppery / orange on the brightened bits, but very little so.  The bottom bit of PB has a patina on the machined section of about the same age as that of the non-brightened turned section on the brass bar - the PB tends to age toward a deeper yellow than the brass.  The un-machined sections of the bars show clearly the difference between raw brass stock and raw PB.

Unfortunately I don't have other types of bronze to compare with; I once machined a bit of "aluminium bronze" and it looks like it says; imagine adding a slight aluminium tint to the PB; it actually is lighter in colour than brass on a clean cut.

Nearly all of my round brass stock is of the "hard bass" type, while all my hex brass stock is softer.  The hard brass turns with cool (temperature) small sharp chips flying off in all directions, while the hex stock (and flat bar) tends to be more gummy to turn and can be stringy.  The phosphor bronze also comes off in small chips - and much hotter.  It's also tougher to  turn than any of the brasses; if the toolbit is just slightly blunt, it actually takes some force at the handwheels, while the brasses just go off like butter.
Too much speed on the PB, and it'll dull a HSS toolbit in short order, and it's a bit more difficult to get a mirror-like turned finish on the PB compared to brass.

Don't know if this helps, or just adds to the problem...

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Firebird on October 22, 2013, 08:43:51 PM
Hi

No problem at all Arnold, any information is always welcome  :ThumbsUp:

I'm pretty much resigned to using what I have now. I have enough material to make 3 wormwheels so even if it doe's wear out I can replace it with one made from similar material.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Pete49 on October 23, 2013, 03:28:42 AM
Now I may be bombarded for this but my take has always been to just use brass if it is on hand. My point being as hobbyists our tools don't get the workout that tradies tools get and so will last us out .....unless we are young  :lolb: Case in point my 4" RT was made with a donated 60t gear (thanks Tel) and at first a recycled bronze worm which halved the gear tooth count and then I made a steel worm working on the premise I will be gone before it wears out.  :old:
Pete
Title: Re: Building a 7" rotary table
Post by: Firebird on October 23, 2013, 09:45:04 PM
Hi

Your'e probably right Pete, anyway I'm going to use the material I have and see how that go's.

I have drilled and tapped each end of the 2 shorter side pieces 6mm and drilled 6.4mm clearance and counter bored each end of the 2 longer side pieces. I used a wiggler to find a corner datum on each piece then drilled using co ordinates to get the holes as accurate as possible. No photos of the drilling operation I don't think I can tell you guys anything about drilling holes. Bolted together they are pretty square.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03808_zpsb69980c7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03808_zpsb69980c7.jpg.html)

In the mill I gave the face a light skim just to get a completely flat surface.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03810_zps8ceef508.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03810_zps8ceef508.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03814_zpsd01254e0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03814_zpsd01254e0.jpg.html)

Next job is to drill through the top plate and drill and tap the sides and bolt it down. At this point I will number stamp each piece in relation to the top plate so that I can disassemble/assemble. I may have to drop down to 5mm cap head bolts for this to leave a little more meat around the sides as I want to eventually machine the sides square. I'm not sure yet whether or not to weld the finished body together, I'll see how solid it feels later.


Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on October 30, 2013, 09:18:52 PM
Hi

With the top plate and sides clamped squarely in the mill I drilled 12 holes, 3 per side,  with a 4.2mm drill through the top and about 15mm deep into the sides. Then a 6.4mm clearance drill through the top plate only then counter bored the top plate with a 10mm end mill. Un clamp and remove the top plate and tap all 12 holes 5mm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03816_zpsd796e5cc.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03816_zpsd796e5cc.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03826_zps060b8261.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03826_zps060b8261.jpg.html)

I have number stamped each side piece and its corresponding position on the underside of the top plate.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03824_zpsbbaa4d7b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03824_zpsbbaa4d7b.jpg.html)

The 2 shorter side pieces have been removed and clamped together in the mill vice and drilled right through with a 1/2" drill. Then the holes are joined up with a 1/2" slot cutter to a depth of .25"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03833_zps90e782b5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03833_zps90e782b5.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03836_zps104f226e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03836_zps104f226e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03838_zpseada448f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03838_zpseada448f.jpg.html)

Cheers

Rich

Title: Re: Building a 7" rotary table
Post by: swilliams on October 31, 2013, 05:36:39 AM
nice stuff Rich, she's starting to come together

Steve
Title: Re: Building a 7" rotary table
Post by: Firebird on November 02, 2013, 05:48:08 PM
Hi

Thanks Steve

Today I have started on the table. I need to mount it on the face plate so started by marking out both sides of the blank.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03840_zpsc6aa2a75.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03840_zpsc6aa2a75.jpg.html)

Then drill and tap the good side with 4 6mm holes.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03841_zps055c626f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03841_zps055c626f.jpg.html)

I have made 4 aluminium spacers drilled 6mm and 4 thick steel washers drilled 6mm.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03843_zps3dde2a1c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03843_zps3dde2a1c.jpg.html)

Fit 4 6mm studs followed by the spacers.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03844_zps38a62d62.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03844_zps38a62d62.jpg.html)

Then drop on the face plate followed by the thick steel washers and nuts. The nuts are just nipped up at the moment.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03846_zpse3a424c7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03846_zpse3a424c7.jpg.html)

With the face plate screwed onto the lathe I centred  the table with a DTI and tightened the nuts.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03849_zps70044a59.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03849_zps70044a59.jpg.html)

Firstly clean up the outer edge. Note here I am using one of my home made tangential cutters. This one has round tool steel fitted and cuts beautifully.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03854_zps4598bcf2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03854_zps4598bcf2.jpg.html) 

Then machine the face of the rotary table. In fact this face will be the underside not the top face.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03857_zps9ffb13c8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03857_zps9ffb13c8.jpg.html)

Here's a short bit of video of the tangential cutter doing its thing.

dVkiMsUoY5Mfeature=share&list=UUxFK_42ytjP4_lA4B2pscxg

You can always tell by the swarf when a cutter is cutting well

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03852_zps9a1f8c14.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03852_zps9a1f8c14.jpg.html)

Cheers

Rich
 
Title: Re: Building a 7" rotary table
Post by: tel on November 02, 2013, 09:51:23 PM
Progressing nicely Rich!  :ThumbsUp:
Title: Re: Building a 7" rotary table
Post by: Firebird on November 03, 2013, 02:07:24 PM
Hi

Thanks Tel

Today I started on the spindle which will end up looking like a flat topped mushroom. A piece of steel about 3" dia is chucked and faced. With the help of a tailstock revolving centre turn down. This is taking quite a while with mountains of curly swarf on the machine and floor. I have to get it down to 1.25" to suit the bearing I am going to use. I'll have to finish it another night.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03861_zps2316205a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03861_zps2316205a.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03864_zps4a08b86a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03864_zps4a08b86a.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on November 05, 2013, 08:06:25 PM
Hi

A bit more turning tonight, its now close to the finished size of 1.25"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03868_zps268ddc5e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03868_zps268ddc5e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03869_zpsbb82d224.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03869_zpsbb82d224.jpg.html)

I noticed the work piece was quite warm. I need this to be a good fit in the bearing that I am going to use so I have decided to leave it to cool down and take the final cuts another time. This is a sizeable lump of steel that gets quite warm during turning, I wonder by how much it increases in size?

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: sco on November 05, 2013, 10:07:29 PM
7.3E-6 in/in per degF

so if my imperial maths is correct the diameter of your bar will increase by ~0.001" for a 100degF increase in temperature.

Simon.
Title: Re: Building a 7" rotary table
Post by: Firebird on November 05, 2013, 10:15:11 PM
Hi

Thanks Simon, probably would'nt be enough to worry about then.

cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: NickG on November 05, 2013, 10:41:42 PM
Rich, I've often wondered the same and thought there must be a fairly simple way to estimate it but have never looked. Turns out there is... the volumetric expansion coefficient for steel is roughly 33e-6 / K depending on the grade, multiplying this by the change in temperature gives the fractional change in volume of the component. An isotropic material expands at the same rate in all directions so length as well as width or diameter. For a simple 1" dia x 1" long steel bar, and a temp increase of 50C I worked the increase in diameter out to be about 0.00067" ... I think! So you're right, if working to a fine tolerance, it could play a part. Might do some experiments with the oven, bit of
1" bar and a mic now!
Title: Re: Building a 7" rotary table
Post by: sco on November 06, 2013, 12:57:05 AM
Nick,

For these kinds of calcs you want the linear coefficient of thermal expansion not the volumetric coefficient.  If you are going to experiment then use Ally as its coefficient is roughly twice steel so the effect will be easier to measure.

Simon.
Title: Re: Building a 7&quot; rotary table
Post by: NickG on November 06, 2013, 12:43:31 PM
Thanks Simon, but why would you use the linear coefficient when it's expanding in all directions?
Title: Re: Building a 7" rotary table
Post by: sco on November 06, 2013, 12:54:23 PM
Because the volume coefficient describes how the volume changes with temperature - you are not measuring the volume change you are measuring a length change.

Simon.
Title: Re: Building a 7&quot; rotary table
Post by: NickG on November 06, 2013, 07:30:10 PM
I thought you would calculate the volume increase then work out the corresponding increase in diameter which is what I did. Didn't think it would expand the same linear distance diametrically as it would length ways if you know what I mean, as a given increase in diameter adds twice as much to the volume as the same increase in length for a cylinder .. or am I talking gibberish? Was struggling to get my head around this last night!
Title: Re: Building a 7" rotary table
Post by: sco on November 06, 2013, 10:03:57 PM
Should be possible to work out the volume increase and then back calculate the increase in diameter but this is definitely the hard way of doing it!

The imperial linear expansion coefficient in words is the amount of expansion in inches per inch per degF change in temperature, so if you have a rectangular bar 1 inch square by 2 inches long and you heat it up then it will expand twice as much along it's length as across it's flats.  Doesn't matter if the bar is inch diameter it will still expand twice as much along it's length as across it's diameter.

Simon.
Title: Re: Building a 7&quot; rotary table
Post by: NickG on November 07, 2013, 08:53:22 AM
Oh yes, that is what I have done just used an extra step for no reason, that's why for an isotropic material the volumetric coefficient is 3x the linear. Thanks, that makes things easier then!
Title: Re: Building a 7" rotary table
Post by: Firebird on November 07, 2013, 08:31:25 PM
Hi

Coefficient of Isotropic volume = volumetric diameter  + thermal expansion assuming the angle of the dangle is perpendicular  to the linear expansion  :noidea: :shrug: :help: :lolb: :lolb: :lolb:

I have absolutely no idea where you guys get all this knowledge from. If you don't mind I'll just take your word for it and look it up later  :happyreader:  :ThumbsUp:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: swilliams on November 07, 2013, 10:49:39 PM
Isotropic is just a fancy physics/maths term. It means the same in every direction. Some materials are not isotropic, but I don't know of any that we would use. A Polaroid sunglasses lens is an example of  something made from an anisotropic material.

"I have absolutely no idea where you guys get all this knowledge from"
That knowledge has university science class written all over it  :Lol:

Steve
Title: Re: Building a 7" rotary table
Post by: Firebird on November 09, 2013, 07:14:17 PM
Hi

I'm afraid I missed most of the science class. I was in full time employment by my 15th birthday and have been ever since. Funny isn't it how all these years later you wish you had paid more attention at school  :happyreader: Well I am learning a few new tricks since taking up this hobby, its just a bit slower to sink in.

Today i finished turning the spindle down to size, the bearing is a good fit. Sorry no photographs today. I need to screw cut a thread on the spindle now and make a couple of nuts to suit. The rest of the afternoon was spent messing around with gears and lathe set ups. I have done some screw cutting once before, a couple of years ago I think, so I need to get my head round it again and have a practice on some scrap. Hopefully I will get out there again tomorrow.

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: NickG on November 09, 2013, 08:53:59 PM
Rich, re sinking in, I've got a degree in mechanical engineering but if I did do that at some point I can't remember it so had to look it up on Wikipedia lol!
Title: Re: Building a 7" rotary table
Post by: Firebird on November 10, 2013, 04:40:46 PM
Hi

I'm not alone then Nick  :Lol:

A bit of screw cutting today. First job was to prepare a bit of steel for the nuts. I need 2, one to hold the spindle into the bearing and adjust it and another to hold the worm wheel.

This is a 3omm drill, the old myford copes with a bit this size as long as I take it steady. It removes a lot of material quite quickly.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03871_zps58b33c1c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03871_zps58b33c1c.jpg.html)

Screw cut a 26tpi thread.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03873_zpsf5e2e94e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03873_zpsf5e2e94e.jpg.html)

Parting off the first nut.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03884_zps22a0ffc7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03884_zps22a0ffc7.jpg.html)

Then swop the chuck back to the spindle and screw cut that.

A bit of video of the spindle being screw cut.

BGVp8lY6sUc
The nut won't quite screw on yet I need to cut a little deeper but time was against me finishing it off.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Ginger Nut on November 11, 2013, 07:25:59 AM
 :happyreader: of this thread most interesting
Title: Re: Building a 7" rotary table
Post by: Firebird on November 11, 2013, 09:25:56 PM
Hi

Thanks Ginger Nut
I finished the screw cutting tonight. It only needed a couple of light passes to clean up the thread before the nuts screwed on.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03889_zps91dedb40.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03889_zps91dedb40.jpg.html)

Parting off took a while. I couldn't get all the way through with my parting tool.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03897_zpsc77997d7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03897_zpsc77997d7.jpg.html)

I had to finish parting with a hacksaw.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03902_zps72ce4293.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03902_zps72ce4293.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: swilliams on November 12, 2013, 03:11:11 AM
Looks nice Rich

Steve
Title: Re: Building a 7" rotary table
Post by: Firebird on November 13, 2013, 08:48:54 PM
Hi

Thanks Steve.

Tonight I machined a recess in the table to accept the spindle. I needed this to be a perfect fit so it was a case of sneak up on it very slowly until it just fits in.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03906_zps7c9c29bc.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03906_zps7c9c29bc.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03911_zps18897527.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03911_zps18897527.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03912_zps15e3aa32.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03912_zps15e3aa32.jpg.html)

I just had time to set up a parting tool and started to cut the groove that the table clamps will sit in.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03916_zps55fe0ce0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03916_zps55fe0ce0.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: SandCam on November 13, 2013, 10:10:48 PM
 :ThumbsUp:
Hi Rich,

That is coming along very nicely, it's amazing what the old Myford can handle if you take your time.

How are you going to fix the spindle to the table? and are you going to put locking grubscrews(with suitable Brass protectors) into the adjusting nuts?

One thing though... how is the worm wheel located relative to the bearing?... I don't see a separate locating face for it.

And what's all this reversing the lathe for... when screwcutting... don't you have a thread indicator dial on the old girl.?
Keep up the good work.

Best regards.

Sandy. :cheers:

Oh! and fill up your oil sight glasses :Lol:
Title: Re: Building a 7" rotary table
Post by: Firebird on November 13, 2013, 10:33:53 PM
Hi Sandy, I'm glad to see you are still keeping an eye on me  :ThumbsUp:

I'm going to drill and tap through into the table and countersink and fix with 3 cap head countersunk screws.

The adjusting nuts I'm going to slit through and then drill and tap and fit a cap head bolt so that it can be locked in position once adjusted.

I'm going to machine a key way in the spindle and worm wheel. The worm wheel will be trapped between the two nuts.

As for reversing the lathe, well this is only my second attempt at screw cutting so I found it easier to do it that way. I do have a thread dial indicator but I need more practice with it.

The sight glasses have a few drops of oil every time I use the lathe but they leak a little so I don't fill them up.

cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on November 17, 2013, 03:28:07 PM
Hi

Today I finished cutting the groove for the clamps.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03927_zpsd41076c8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03927_zpsd41076c8.jpg.html)

I now needed to drill 4 holes in the spindle and drill and tap 4 holes in the table. I did say 3 holes earlier but I have decided to do 4. I intend to cut 4 T slots in the table and I don't want to hit any screws, the T slots can go between the screws.

I have an adapter for the myford that takes the screw on chucks etc.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03931_zps6f5a0e40.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03931_zps6f5a0e40.jpg.html)

Here I have mounted it in the rotary table and centreing it.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03932_zps03deef27.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03932_zps03deef27.jpg.html)

This shows the limits of an X3 mill. The head is at its maximum height.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03933_zps606dd268.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03933_zps606dd268.jpg.html)

Drilling.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03936_zpsccfe0c96.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03936_zpsccfe0c96.jpg.html)

After drilling and tapping and counter sinking. The screws are slightly over long at the moment so I can't tighten it down fully.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03938_zpsb7ad3bda.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03938_zpsb7ad3bda.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on December 29, 2013, 02:05:48 PM
Hi

Its been a while hasn't it. Iv'e been ill and then there was xmas but today I felt up to going out in the workshop for a couple of hours. After a bit of tidying up I set to with a bit of light work.

The two nuts I screw cut were held in the vise and had a pocket machined in them.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03991_zps6ee7c8b6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03991_zps6ee7c8b6.jpg.html)

Followed by a tapping size drill. I have used 5mm on the larger one and 4mm on the smaller one.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03999_zps5fce11d9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03999_zps5fce11d9.jpg.html)

Then slit them

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04001_zps2c1c9778.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04001_zps2c1c9778.jpg.html)

Followed by a clearance drill through the top half only.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04003_zps7ca948e2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04003_zps7ca948e2.jpg.html)

Already there are signs of rust appearing on the new machined surfaces so I have blacked and oiled the two parts.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04004_zpscbe11e65.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04004_zpscbe11e65.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04007_zpse7ea9ec6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04007_zpse7ea9ec6.jpg.html)

cheers

Rich
Title: Re: Building a 7" rotary table
Post by: sco on December 29, 2013, 03:21:57 PM
Nice - good to see you making swarf again!

Simon.
Title: Re: Building a 7" rotary table
Post by: NickG on December 31, 2013, 01:33:02 PM
Good stuff Rich, I really need to get out in New Year, think I've got most of the tools i'll need now so no excuses!
Title: Re: Building a 7" rotary table
Post by: Firebird on December 31, 2013, 02:00:58 PM
Hi

Thanks Nick and Simon.

A bit more turning today. This is the bit that the bearing will fit into.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04009_zps668a4b90.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04009_zps668a4b90.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04013_zps27b06995.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04013_zps27b06995.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04011_zps48f860f0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04011_zps48f860f0.jpg.html)

Then I centred the box top plate in the mill. Note here I'm using my new bluetooth system and tablet for the DRO's

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04018_zps50101c29.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04018_zps50101c29.jpg.html)

4 holes are drilled and counter sunk, these are to fix the bearing carrier in place, and a centre hole drilled.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04017_zpseea6e4bc.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04017_zpseea6e4bc.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on January 09, 2014, 07:53:44 PM
hi

I needed to bore a hole through the top plate so set it up in the mill and drilled a hole with the biggest drill I have.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04024_zps1e5bb7eb.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04024_zps1e5bb7eb.jpg.html)

I tried opening out the hole with a boring head but didn't get on too well. There was a lot of chatter and the machine shook about a lot, I am putting it down to the cheap TCT tools that came with the boring head. When time permits I'll have another go with it and maybe make up some tools of my own to go with it. Sorry no photos of the boring head. I transferred the top plate to a face plate mounted on a rotary table and centred it with a DTI.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04027_zps3eea5cb9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04027_zps3eea5cb9.jpg.html)

Then with a 10mm cutter removed metal.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04032_zps3a77ec61.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04032_zps3a77ec61.jpg.html)

Until the bearing holder was a nice fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04034_zpse5bb3294.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04034_zpse5bb3294.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on January 13, 2014, 08:49:58 PM
Hi

The top plate and bearing holder are clamped to mill table and the 4 holes spotted through then drilled tapping size for 5mm.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04039_zps9e48ca35.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04039_zps9e48ca35.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04038_zps39c36b63.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04038_zps39c36b63.jpg.html)

Tap the holes.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04042_zpsd4f1b16e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04042_zpsd4f1b16e.jpg.html)

AAAAAAAAAAARRRRRRRRRRRRRGGGGGGGGGGGGHHHHHHHHHHHHHHH no no no  :cussing: :facepalm:

A broken tap :'( :'( :'(

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04044_zps17f869b1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04044_zps17f869b1.jpg.html)

After about half an hour of gentle tapping with a centre punch I got the little critter out.  :whoohoo:

Now come on, how often do you get that kind of luck  :cartwheel:

I think I might go and buy a lottery ticket.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04046_zpsd6caa585.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04046_zpsd6caa585.jpg.html)

Fix the two parts together, the countersunk cap head screws are just a touch too long so I need to shorten them.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04052_zpsaf159f8a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04052_zpsaf159f8a.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04054_zpsb45908a4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04054_zpsb45908a4.jpg.html)

Fit the bearing.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04056_zps04af95d5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04056_zps04af95d5.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04057_zps0fcd4221.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04057_zps0fcd4221.jpg.html)

Push the spindle through.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04059_zpsaef22699.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04059_zpsaef22699.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04060_zpsbe18bb14.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04060_zpsbe18bb14.jpg.html)

screw on one of the adjustable lock rings

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04063_zps6710a100.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04063_zps6710a100.jpg.html)

I think I will have to make the gear next when time permits.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Bluechip on January 13, 2014, 09:16:51 PM
Rich

You need some of Ketan's Serial Taps   . :ThumbsUp:

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Taps/Serial-Taps---Metric-BSW-BSF

Even a ham-fisted oaf such as myself would be challenged to break them ..

Dave
Title: Re: Building a 7" rotary table
Post by: Don1966 on January 14, 2014, 01:28:56 AM
All I can say is you have to be living right. Those tapes never come out for me. You have done some very nice work on this one Rich and it looks better then the ones you buy. I ilke......... :ThumbsUp:

Don
Title: Re: Building a 7" rotary table
Post by: Pete49 on January 14, 2014, 01:52:12 AM
Good to see you back at it. watching with interest still.
Pete
Title: Re: Building a 7" rotary table
Post by: steamer on January 14, 2014, 02:46:03 AM
Nicely done Rich!.....Is the bluing anything fancy or just standard stuff?

Additionally, what numbers did you chose for the lottery...... 8)

Dave
Title: Re: Building a 7" rotary table
Post by: Firebird on January 14, 2014, 07:29:26 PM
Hi

Dave I have some of Arcs tap sets they are very good. In this instance I used a taper tap first then the plug with plenty of tapping grease on both but hey ho taps do break.

Don and Pete thanks for watching :ThumbsUp:

Dave the bluing (or is it blacking) is a kit I bought from a model engineering show about 3 years ago, I forget the make now. It consists of 4 parts, de greasing, conditioning, blacking and oiling.

As for the lottery I will have a lucky dip.

cheers

Rich

Title: Re: Building a 7" rotary table
Post by: Firebird on January 19, 2014, 03:30:34 PM
Hi

I have made a start on the worm gear. The piece of brass/bronze is cleaned up internally and externally then parted off.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04078_zps743bcaa8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04078_zps743bcaa8.jpg.html)

a piece off steel turned to suit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04080_zps8461ebcd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04080_zps8461ebcd.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04084_zpsd10fbfe8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04084_zpsd10fbfe8.jpg.html)

Press into place. Its a comfortable fit not too tight, the press makes sure its pushed on square.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04088_zpsfed32c71.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04088_zpsfed32c71.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04089_zps8112080a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04089_zps8112080a.jpg.html)

Finally today without removing the workpiece from the chuck I centred it in the mill.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04090_zps5377d74f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04090_zps5377d74f.jpg.html)

I am going to drill and tap 5mm around the joint and fit 4 grub screws which will make sure the 2 parts can't move.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04093_zps3543542b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04093_zps3543542b.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: arnoldb on January 19, 2014, 04:36:02 PM
Quote
I am going to drill and tap 5mm around the joint and fit 4 grub screws which will make sure the 2 parts can't move.

 :ThumbsUp:

Good going Rich

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Arbalest on January 19, 2014, 08:26:05 PM
Nice work Rich!  :ThumbsUp:
Title: Re: Building a 7" rotary table
Post by: Firebird on January 26, 2014, 03:16:18 PM
Hi

Drilled and tapped the 4 holes

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04099_zps2e9a4b0d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04099_zps2e9a4b0d.jpg.html)

Fitted the 4 brub screws with a drop of loctite

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04100_zpsa7c8b53a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04100_zpsa7c8b53a.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04101_zps6aa5fdb4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04101_zps6aa5fdb4.jpg.html)

Returned the chuck to the lathe and turned to size. I would have liked a little more meat on the brass/bronze but I'm working to materials I have so I'll see how it goes.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04104_zps40208b62.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04104_zps40208b62.jpg.html)

Bore out the centre

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04109_zps7057540a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04109_zps7057540a.jpg.html)

Until the spindle fits

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04110_zps3b719871.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04110_zps3b719871.jpg.html)

Cut a keyway. This is tedious job a thou at a time but it works.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04112_zps0d598cb7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04112_zps0d598cb7.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04119_zps3a25cf3b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04119_zps3a25cf3b.jpg.html)

Then part off

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04129_zpsd584c896.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04129_zpsd584c896.jpg.html)

a trial fit in the bearing

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04134_zpsdae4eb89.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04134_zpsdae4eb89.jpg.html)

and in the case

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04135_zps6e0b5d65.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04135_zps6e0b5d65.jpg.html)

Turn an arbor in the lathe to hold the gear and transfer to the mill and rotary table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04137_zps8a23a61a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04137_zps8a23a61a.jpg.html)

Mill a keyway

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04138_zpsdf061827.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04138_zpsdf061827.jpg.html)

I have ordered some key steel but for now a bit of square brass will do

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04149_zpsf455642e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04149_zpsf455642e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04152_zps1e94f473.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04152_zps1e94f473.jpg.html)

Make a thick steel washer and fit an 8mm cap head bolt

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04156_zpse67d4ebd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04156_zpse67d4ebd.jpg.html)

Check that things are still running true

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04158_zps8b4df067.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04158_zps8b4df067.jpg.html)

A digital angle guage set to zero on the mill table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04159_zpsc2bd2647.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04159_zpsc2bd2647.jpg.html)

Then tilt to 2.65°. The angle guage only reads to one decimal point so I have to feel my way between 2.6 and 2.7

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04161_zps71245ce4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04161_zps71245ce4.jpg.html)

Set up a slitting saw and cut to a depth of .040 inches. Note here I'm using my phone as the bluetooth DRO reader. Its raining out so I didn't want to run to the house to fetch my tablet.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04164_zpsf985353d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04164_zpsf985353d.jpg.html)

Cut 90 teeth

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04173_zps23f4a898.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04173_zps23f4a898.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04174_zpsb4f2ed6c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04174_zpsb4f2ed6c.jpg.html)

As an extra precaution I have decided to fit 4 button head screws into the gear. They are drilled and tapped into the steel centre but their heads overlap onto the gear.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04181_zps04b012b7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04181_zps04b012b7.jpg.html)

I need to set up in the lathe now and cut the teeth but that will have to wait for another day.

Cheers

Rich



Title: Re: Building a 7" rotary table
Post by: sco on January 26, 2014, 07:45:11 PM
Nice work cutting that gear - impressive!  What are the button head screws for?

Simon.
Title: Re: Building a 7" rotary table
Post by: Firebird on January 26, 2014, 08:22:06 PM
Hi Simon

The brass gear is a light press fit onto the steel hub. I drilled and tapped around the joint and fitted grub screws to prevent the two parts turning around each other. Its probably enough to hold the gear onto the hub but I felt it just needed a little extra.

cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on January 27, 2014, 08:32:55 PM
Hi

pinched a half hour tonight while the wife went to weightwatchers. Tapped the 4 holes 4mm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04183_zps4340ba04.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04183_zps4340ba04.jpg.html)

And fitted the screws

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04185_zps85deab89.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04185_zps85deab89.jpg.html)

Thats better, no chance of it moving or coming off now.

Back to the lathe to turn a mandrel for the gear to spin on when cutting the teeth

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04186_zps053fa8f4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04186_zps053fa8f4.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04187_zpsbe8a2716.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04187_zpsbe8a2716.jpg.html)

Then part off

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04188_zps91a7f0b6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04188_zps91a7f0b6.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04189_zpsc84e75a5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04189_zpsc84e75a5.jpg.html)

I need some decent time now to set up in the lathe to cut the teeth, got to get this bit right. Hopefully this weekend.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Jo on January 27, 2014, 09:53:43 PM
while the wife went to weightwathers.

 :headscratch: Why do they do that? Waste of good workshop time and giving away money that would be better spent on.. castings.. tools.....or even bottles of better wine  :slap:

Why dont you offer to lend her your hacksaw and she can loose weight by keeping fit cutting a few bits of metal for you  ;D

Jo
Title: Re: Building a 7" rotary table
Post by: Firebird on January 27, 2014, 10:43:53 PM
some nice ideas there Jo but while the wifes away I can play :Lol: :Lol:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on January 29, 2014, 08:39:34 PM
Hi

I'm doing well this week, another hour in the shop :cartwheel:

Time to cut the worm gear.

Set up in the lathe

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04197_zps0c71d923.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04197_zps0c71d923.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04199_zps45d8290b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04199_zps45d8290b.jpg.html)

A bit of video

JuFhBTadDP8feature=share&list=UUxFK_42ytjP4_lA4B2pscxg

Not too bad at all, I think that'll do

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04203_zpsfaf27bc6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04203_zpsfaf27bc6.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on February 09, 2014, 03:17:44 PM
Hi

I have cut the keyway on the spindle.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04212_zps5fae4c2b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04212_zps5fae4c2b.jpg.html)

Checking the depth. Handy little gadgets these digital tyre tread depth guages.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04211_zps2318c00d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04211_zps2318c00d.jpg.html)

A piece of 3/16 square key steel filed to shape and fitted.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04218_zpsf112565a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04218_zpsf112565a.jpg.html)

Followed by the gear.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04221_zps9009701a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04221_zps9009701a.jpg.html)

I had to drill and tap the back of the table 6mm to fit it to my face plate.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04223_zps62236d4a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04223_zps62236d4a.jpg.html)

Then face it.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04226_zps12f6b9d5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04226_zps12f6b9d5.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: zeeprogrammer on February 09, 2014, 03:30:06 PM
The screw cutting was pretty interesting and I watched the video.
But I'm not sure I understand...
Does the gear rotate automatically as the hob cuts?
Is it a single pass? If not, how do you ensure that the second pass is right on?
I missed the part where you first cut the 'slots' on the gear before using the hob. How was that done?
Thanks.
Title: Re: Building a 7" rotary table
Post by: Firebird on February 09, 2014, 04:41:39 PM
Hi Carl

If you go back to page 1 you will see how I learnt to do it with the help of many friends  :ThumbsUp: here on this forum.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: zeeprogrammer on February 09, 2014, 05:48:38 PM
Ah thanks Rich. And my apologies for not having been up to speed on your thread.
Really good information here.
Title: Re: Building a 7" rotary table
Post by: arnoldb on February 14, 2014, 03:50:07 PM
The gear came out very nicely Rich  :ThumbsUp:

Love the use of the mirror in your video - I might have to borrow that idea at some point  :)

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: SandCam on February 14, 2014, 04:48:03 PM
Hi Rich,

Very nice job on that wormwheel, I think you have the hobbing method down pat now.

The rotary table is making excellent progress and should prove to be a worthy addition to your arsenal.

Next critical job will be the matching WORM... don't forget, this must be the same OD as the TAP used for hobbing or the HELIX angle will not be correct. :facepalm2:

Looking forward to the next chapter.

Best regards,

Sandy. :cheers:
Title: Re: Building a 7" rotary table
Post by: Firebird on February 15, 2014, 07:25:01 PM
Hi

Thanks Arnold, I'm pleased with it. I only had one shot at it so had to get it right first time.

Nice to here from you Sandy. The worm gear will come soon but first I need to work out how to make the eccentric to disengage it and also I would like to incorporate a means of power driving the table :thinking: :thinking:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on April 19, 2014, 08:57:30 PM
Hi

Over 2 months since my last post, not good enough is it  :( but today I had a good day at it :whoohoo:

When I took the cover off the lathe I was greeted with a rusty table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04271_zps01db1c83.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04271_zps01db1c83.jpg.html)

A quick clean up with a scouring pad and it was back to looking good. I have drilled and reamed a 1/2" hole in the centre while it was still set up to give me something that will take various adapters.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04273_zps25ae28df.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04273_zps25ae28df.jpg.html)

Then starting from the outside I machined some guide rings every 1/2"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04276_zpsab73f3c0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04276_zpsab73f3c0.jpg.html)

Next I moved on to the eccentric. Turn a piece of steel down to 1.4" and drill a centre mark.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04285_zps2706b3bd.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04285_zps2706b3bd.jpg.html)

Centre in the mill and move over .25" and centre drill again. Dead easy using my DRO on my tablet.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04288_zps07528e93.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04288_zps07528e93.jpg.html)

Back in the lathe and centre in the 4 jaw using a DTI  and spring loaded pointer.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04293_zpsbc5cff37.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04293_zpsbc5cff37.jpg.html)

Drill through with a 3/8 drill. The spindle I'm going to use is 8mm, salvaged from a car tail gate gas strut. 3/8 gives a bit of clearance for the 8mm. Sorry about jumping from imperial to metric but I use what I have and I'm comfortable switching.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04296_zpsc96f11bb.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04296_zpsc96f11bb.jpg.html)

I have some bearings 14mm OD x 8mm ID x 4mm thick

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04297_zps9b800627.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04297_zps9b800627.jpg.html)

Bore a pocket with a 14mm end mill

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04298_zps3ae1aa0c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04298_zps3ae1aa0c.jpg.html)

Try a bearing for fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04303_zpsdde2d9c7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04303_zpsdde2d9c7.jpg.html)

Turn around and re centre using the 3/8" drill.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04305_zpsafe63a41.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04305_zpsafe63a41.jpg.html)


And machine the other bearing pocket. Then a trial fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04307_zpsb9173a43.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04307_zpsb9173a43.jpg.html)

Moving on to the worm the first job was to prepare a steel blank. Turned to 3/4" to match the 3/4" whitworth tap I used to cut the wheel. 2 runouts machined to .064 deep, the thread depth of 3/4" whitworth.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04312_zps19dd6609.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04312_zps19dd6609.jpg.html)

Set the 55° tool. the top slide is set over to 27.5°.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04315_zps744e150f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04315_zps744e150f.jpg.html)

The gear set up for 10TPI. I have a little computer programme for the myford which gives me the setup. I asked for 10TPI and it gave 118 different ways! Take your pick.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04319_zps7e971216.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04319_zps7e971216.jpg.html)

After screw cutting.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04322_zps1e5d2a0c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04322_zps1e5d2a0c.jpg.html)

In the mill to be tapped 5mm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04324_zpse47149b1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04324_zpse47149b1.jpg.html)

For grub screws

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04326_zps967d280c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04326_zps967d280c.jpg.html)

Then remove the side that will have the hole bored in it. A good photo opportunity.

 (http://i242.photobucket.com/albums/ff17/firebird_021/DSC04327_zpse530440f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04327_zpse530440f.jpg.html)

A trial fit of the worm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04328_zps11745a5a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04328_zps11745a5a.jpg.html)

Bore a hole in the side plate. I was careful to get this bang on the 1.4" so that the eccentric is a good fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04330_zpsf0e8bf8b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04330_zpsf0e8bf8b.jpg.html)

Another trial fit. Starting to look like a rotary table now.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04337_zps0c77e539.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04337_zps0c77e539.jpg.html)

Inside view of the worm engaged

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04338_zpsb1e58284.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04338_zpsb1e58284.jpg.html)

And disengaged

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04339_zpsb860164d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04339_zpsb860164d.jpg.html)

Machine 2 flats on the spindle

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04342_zps37a83e5d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04342_zps37a83e5d.jpg.html)

Another trial fit

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04343_zps291b8ae0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04343_zps291b8ae0.jpg.html)

Although I was very careful to bore the hole accurately I feel it will benefit from a bit more meat so I am going to fit a bit more steel plate to the outside.

In the 4 jaw being bored to 1.4"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04346_zpsa3dcb477.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04346_zpsa3dcb477.jpg.html)

Checking the fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04348_zpsa391bcb1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04348_zpsa391bcb1.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04350_zpse4c59c63.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04350_zpse4c59c63.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04351_zpsf0eb68c8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04351_zpsf0eb68c8.jpg.html)

A satisfying days work. Hopefully it won't be as long before some more is done.

Cheers

Rich











Title: Re: Building a 7&quot; rotary table
Post by: ths on April 19, 2014, 10:54:20 PM
What a great day you had there. Looks like the fits are spot on.

Cheers, Hugh.
Title: Re: Building a 7&quot; rotary table
Post by: NickG on April 21, 2014, 09:30:12 PM
Looks great that Rich, well done.
Title: Re: Building a 7" rotary table
Post by: Firebird on April 26, 2014, 09:32:01 PM
Hi

I'm not happy with the way the eccentric works/feels so I'm trying something else. I have bored out the eccentric which I will now screw to the frame making a more solid bush. I'm then going to make an inner eccentric that is a good sliding fit in the bush. That should be much more rigid.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04363_zpsa93274d9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04363_zpsa93274d9.jpg.html)

The boring bar I use is home made, very easy to make. A length of round steel bar is drilled and tapped 1/4" for a grub screw and cross drilled 3/16". The shank has 3 flats milled to fit into the tool holder. The 3/16" round tool steel is ground using the tangential cutting tool jig (see my post on making a tangential tool).

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04364_zps8d834cde.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04364_zps8d834cde.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04371_zps43cf93c2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04371_zps43cf93c2.jpg.html)

It cuts beautifully and leaves a very good finish.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on April 27, 2014, 03:50:32 PM
Hi

After boring out to 1.125"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04372_zps2eaaaa3e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04372_zps2eaaaa3e.jpg.html)

A piece of scrap ally turned to 1.125" and a 8mm hole drilled with .125" offset

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04374_zps601a8743.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04374_zps601a8743.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04375_zpse5e616f1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04375_zpse5e616f1.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04378_zps153403ac.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04378_zps153403ac.jpg.html)

Thats better, more rigid. I can make a steel one now the same length as the bush which should result in virtually zero play.

cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on April 30, 2014, 09:05:52 PM
Hi

Started turning the new eccentric tonight, its a straightforward turning job of little interest to you experienced guys  ;D but it occurred to me that not too long ago I was a newbie to all this and keen to learn  :headscratch: so I thought I'd show it for the benefit of all current newbies. I have to turn a piece of 55mm dia steel down to around 28mm. I always try taking a cut at the lathes slowest speed and if there is any sign of chatter I switch to an even slower speed by using the back gear. Takes a while longer to get there but the cuts are nicer and there is less strain on the machine. I am using my home made power feed and home made tangential cutter.

30OV-7P5SBE
Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: zeeprogrammer on April 30, 2014, 09:57:18 PM
Very helpful to see videos of cutting in progress. Thanks.

How much were you taking off in that pass?
Title: Re: Building a 7" rotary table
Post by: Firebird on April 30, 2014, 11:30:43 PM
Hi Carl

010" at a time.

cheers

Rich
Title: Re: Building a 7" rotary table
Post by: joe d on May 01, 2014, 12:51:33 AM
Hi Rich

I've been following along since the beginning, and just wanted to say that I've been enjoying it.

Looking forward to more!

Thanks,  Joe
Title: Re: Building a 7" rotary table
Post by: Firebird on May 03, 2014, 09:31:57 PM
Hi

Thanks Joe.

A bit more turning done and then a groove that the locking screw will locate into.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04385_zpsdf4c2b3b.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04385_zpsdf4c2b3b.jpg.html)

Cut from the parent material

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04389_zps76aa3c2f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04389_zps76aa3c2f.jpg.html)

After facing it is moved to the mill to have a centre drill mark. This time I have made the offset just 0.1"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04392_zps6edf6589.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04392_zps6edf6589.jpg.html)

Re centred in the 4 jaw

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04394_zps9c6ef4e4.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04394_zps9c6ef4e4.jpg.html)

and drilled through 3/8"

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04396_zps542f4c13.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04396_zps542f4c13.jpg.html)

Then a pocket machined with a 14mm end mill for the bearing, sorry no photo. Turn it round and recentre using the 3/8" drill

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04402_zps9645de96.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04402_zps9645de96.jpg.html)

Then another bearing pocket, followed by a trial fit.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04405_zps93356b3c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04405_zps93356b3c.jpg.html)

Centred again, I'm getting quick at using the 4 jaw. The outer part is turned true with the spindle hole.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04406_zpsebefae42.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04406_zpsebefae42.jpg.html)

The bush is in the mill having 2 x 4mm holes drilled and counter bored to take socket head screws. I'm a bit tight for room so I have turned the heads of the screws down a bit and used a 1/4" cutter to counter bore

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04411_zps1f82d13e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04411_zps1f82d13e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04416_zpsb6459926.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04416_zpsb6459926.jpg.html)


Drill and tap the side plate.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04419_zps62d4f3d8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04419_zps62d4f3d8.jpg.html)

And fit the bush.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04421_zpsf402771f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04421_zpsf402771f.jpg.html)

A great improvement on the first attempt.

cheers

Rich
 
Title: Re: Building a 7" rotary table
Post by: Firebird on May 04, 2014, 09:55:41 PM
Hi

This is the handwheel on my vertex rotary table

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04433_zps4e123ebe.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04433_zps4e123ebe.jpg.html)

I need to make something similar so have started with a piece of aluminium, another turning job.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04427_zpsed35943c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04427_zpsed35943c.jpg.html)

Cheers

Rich

Title: Re: Building a 7" rotary table
Post by: Firebird on May 06, 2014, 09:37:38 PM
Hi

I have drilled an 8mm hole through the centre and now I need to cut a keyway. I have some 1/8" key steel so that'll do. When I got in from work tonight the wife said dinner will be a bit late I want to finish this ironing. Being the kind considerate chap that I am I said no problem I'll keep out of your way and go in the workshop for a half hour ;D

Thats just enough time to make a keyway cutter. I can't remember where I saw this idea but its a neat little trick. Take a piece of 8mm round steel and mill a 1/8" slot 1/8" deep. I have milled the slot the same length as the bit of 1/8" tool steel I have, no need to cut it down. Drill and tap a 3mm hole at the front end.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04442_zpsc3593ad0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04442_zpsc3593ad0.jpg.html)

Check the tool steel fits ok

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04444_zpsc3e3580c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04444_zpsc3e3580c.jpg.html)

The depth of cut is adjusted by screwing in the 3mm grub screw

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04450_zps8fdbcd47.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04450_zps8fdbcd47.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04460_zps77848496.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04460_zps77848496.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04463_zpsbac2d6e2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04463_zpsbac2d6e2.jpg.html)

The tool is used in the tail stock and wound in and out of the hole adjusting the grub screw until the correct depth is achieved

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04465_zps4153cec9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04465_zps4153cec9.jpg.html)

Unfortunately the ironing is finished and dinner is ready so cutting the keyway is going to have to wait.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: zeeprogrammer on May 07, 2014, 01:27:01 AM
Neat.

Unfortunately the ironing is finished and dinner is ready so cutting the keyway is going to have to wait.

Argh!
Title: Re: Building a 7" rotary table
Post by: Don1966 on May 07, 2014, 01:36:44 AM
Aw man that's the pits Rick!  :lolb: Nice progress and I think I seen that method used before and I think it was in Ruby Kouhoupt's book. It works real well from what I've seen. Still following along.

 :popcornsmall:

Don

Title: Re: Building a 7" rotary table
Post by: PStechPaul on May 07, 2014, 04:21:44 AM
I've thought about making something like that if I need to cut a keyway. But I wonder just how much material can be removed on each stroke, and where the chips will go. There seems to be an angle cut on the tip of the tool which should act as a chisel (or broach), and there may be some space in the slot to hold the chips. But perhaps there could be a larger opening, and it may be good to look at the design of the cutting edge. How much pressure is needed for the cut? Can the tool be held in a chuck on the tailstock and use that to cut the slot? Is it OK for steel?
 
Also, won't the cutting tip angle tend to dig in and raise the tool out of the slot? Maybe the cutter needs to stay parallel to the shaft. Or, perhaps cut a small notch on the tip that will follow the previously cut slot and keep it from lifting? Am I asking too many questions??  :shrug: 

 
I found a web page describing a somewhat different keyway cutter:
http://homepage3.nifty.com/amigos/slotter/slotting_tool-e.htm (http://homepage3.nifty.com/amigos/slotter/slotting_tool-e.htm)
 
Here's a video showing something similar being used on a lathe:
 
https://www.youtube.com/watch?v=7dMDOhlp0rE
Title: Re: Building a 7" rotary table
Post by: Firebird on May 07, 2014, 10:45:59 PM
Hi

Thanks Carl and Don.

I can't answer any of your questions as yet Paul but you raise some good points, time will tell when I try it. One thing though its a through hole so the chips should be pushed out the other side. I'll let you know how well it works (or not)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 11, 2014, 04:16:58 PM
Hi

Well the key way cutter worked well. Light cuts required not too much effort.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04473_zpsd8713679.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04473_zpsd8713679.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04476_zps979704ad.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04476_zps979704ad.jpg.html)

I would think its possible to cut steel this way as well, with light cuts.

The hand wheel is centred accurately in the rotary table on the mill.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04506_zps6dd84589.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04506_zps6dd84589.jpg.html)

I ground a point on a piece of 1/4" round tool steel and scribed all the marks on the dial part.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04507_zps40ec3e4d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04507_zps40ec3e4d.jpg.html)

And stamped in the numbers.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04513_zpse931ba5e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04513_zpse931ba5e.jpg.html)

The table with bush mounted in the mill and drilled and tapped 6mm for the locking screw.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04519_zpsc0e7d16c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04519_zpsc0e7d16c.jpg.html)

The locking screw I made from a cut down high tensile cap head screw, cross drilled and a piece of 1/8" round silver steel for a bar

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04524_zps38c0f385.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04524_zps38c0f385.jpg.html)

Finally today I got my blacking kit out and treated a few of the parts. It helps to keep the dreaded rust at bay.
(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04525_zps8ef42b86.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04525_zps8ef42b86.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04529_zps77042a09.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04529_zps77042a09.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 14, 2014, 08:48:37 PM
Hi

Because the hand wheel is aluminium and the eccentric steel there is bound to be wear. I need to tighten the hand wheel fairly tight to reduce backlash so I have decided to fit a thrust bearing between the two. The bearing is 35mm diameter and 4mm thick. cost less than £5.00 off ebay.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04533_zps4dda62c0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04533_zps4dda62c0.jpg.html)

Centre the hand wheel in the 4 jaw again

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04531_zps3d4fb973.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04531_zps3d4fb973.jpg.html)

Machine a pocket for the bearing about 2.5mm deep.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04537_zps7225d602.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04537_zps7225d602.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04536_zps307ee046.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04536_zps307ee046.jpg.html)

Centre the eccentric and machine about 1mm deep

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04538_zpsb4548f97.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04538_zpsb4548f97.jpg.html)

When together there is about a .5mm gap between the two

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04545_zps5e4317d6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04545_zps5e4317d6.jpg.html)

Assembled the hand wheel spins freely.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04549_zps0bf621c2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04549_zps0bf621c2.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 17, 2014, 08:48:34 PM
Hi

Getting popular these rotary table builds aren't they

Not too much to report on my effort this week, just one little job completed. I need to cut a 8mm thread on the end of the hand wheel spindle. Its fairly hard steel so I decided to have a go at screw cutting the thread. I have screw cut a couple of threads before but its not something I'm confident at. My trusty old myford is imperial but with the right gears it is possible to cut metric threads.

Heres the gear set up

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04555_zpsc1736429.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04555_zpsc1736429.jpg.html)

I did a test cut on a piece of 8mm mild steel bar, the threads not bad but not really good enough. On closer inspection I could see that the cheapo brazed TCT tool I am using has chipped right on the point, you can just see it. I am going to have a go at grinding a tool myself and see how that goes.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04552_zps7e29fdf9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04552_zps7e29fdf9.jpg.html)

Cheers

Rich

Title: Re: Building a 7" rotary table
Post by: Firebird on May 18, 2014, 04:43:34 PM
Hi

Well I had a go at hand grinding a tool and didn't get on too well, theres more to it than I thought  :help: A quick search on google  :atcomputer: led me to a youtube video by Tubal Caine which shows how to make a jig for grinding. Now I could spend a long time acquiring the skills to hand grind or I could spend an hour making a jig that will get it right every time,   :thinking: bit of a no brainer really.

So a lump of scrap ally in the rotary table has two 1/4" slots milled. Turn the table 30° one way and mill the slot. Return to 0° then turn 30° the other way and mill the second slot.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04558_zpsc6411dab.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04558_zpsc6411dab.jpg.html)

Stamp 60° to identify

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04561_zpse1102dbe.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04561_zpse1102dbe.jpg.html)

While its set up turn it over and mill two slots for 55° by turning the rotary table 27.5° each side of 0°

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04562_zps3b1b9ada.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04562_zps3b1b9ada.jpg.html)

Drill and tap 6mm each side and make a clamp

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04566_zpsa33f47b3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04566_zpsa33f47b3.jpg.html)

My home made disc sander has a tilting table. I tilted the table a little to give some side relief to the tool.
(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04567_zps1a19c977.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04567_zps1a19c977.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04569_zps2f3184ba.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04569_zps2f3184ba.jpg.html)

About an hours work and well worth the effort. I can now grind tools quickly and easily evry time.  :cheers: Tubal Caine

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04571_zpsb5408ad3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04571_zpsb5408ad3.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04572_zpsd95a1bf0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04572_zpsd95a1bf0.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04573_zps85b8330a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04573_zps85b8330a.jpg.html)

The tool cuts the thread very easily. Not a very good photo here but theres a better one to follow.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04575_zps3c511b5c.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04575_zps3c511b5c.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04579_zps1ffb8f18.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04579_zps1ffb8f18.jpg.html)

The spindle in the mill having a 1/8" key way slot cut

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04581_zps14bdf6e1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04581_zps14bdf6e1.jpg.html)

After cutting the key way slot. This photo shows how nicely the screw cutting tool has cut.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04585_zpsf1ca4fce.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04585_zpsf1ca4fce.jpg.html)

I'm beginning to think that I put too much faith in TCT tooling. Its nice but very expensive. Having had a lot of success with my home made tangential cutter, which leaves a superb finish, I'm now leaning more towards grinding my own tools. The jigs are quite easy to make and ensure constant results.

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: NickG on May 18, 2014, 04:54:12 PM
That jig is good Rich and has made a good thread, I recently had same trouble hand grinding for a thread. sure I've seen people put a grind wheel in lathe and set compound slide to desired angle though you'd need some wedge shaped packing (I guess) to get the relief? Lathe may not be fast enough really for grinder either so jig is better esp with your sander. I always poo poo'd tct for hobby work as I've had better results in the past with hss. However with my myford I've been using the tct tools I got for xmas one year and had good results. This is more for convenience as they fit nicely in the QCTP and can't be bothered to grind a big set of tools!
Title: Re: Building a 7" rotary table
Post by: Arbalest on May 18, 2014, 06:02:57 PM
I can grind most lathe tools by hand but struggle with thread cutting bits. I saw that jig a little while ago so it's very much on my "to do list". Thanks for reminding me!
Title: Re: Building a 7" rotary table
Post by: arnoldb on May 20, 2014, 07:11:09 PM
Looks great Rich  :ThumbsUp:

The finish on the sharpened edges of a screw-cutting tool makes a huge difference, and your disc sander leaves a nice smooth finish.  I just finish-hone my own ground bits on the fine side of a trusty old whetstone.  Just a suggestion if I may: round the tip of the "V" on the toolbit ever so slightly - otherwise it easily breaks of, normally damaging the cutting edges further back in the process - especially if your bit's been ground a bit hot like the one you showed.  Don't ask how I know that  :LittleDevil:

Kind regards, Arnold
Title: Re: Building a 7" rotary table
Post by: Firebird on May 20, 2014, 07:49:01 PM
Hi

Thanks Nick, Arbalast and Arnold.

Arnold, it got a bit hot from my hand grinding efforts. When I get some spare time  ::) I'm going to grind up a set of cutters ready to use and I'll try honing and rounding the tip.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 21, 2014, 08:23:28 PM
Hi

I have bolted the frame and top plate together, hopefuly for the last time, and mounted it upside down on the mill. A light skim all round was all it needed.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04589_zps305913bb.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04589_zps305913bb.jpg.html)

I am using a piece of 4mm thick ally plate for the base/cover. Steel would be better but I don't have anything suitable so ally it is. Drill tap and countersink for 5mm countersunk socket head screws.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04591_zps29bab792.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04591_zps29bab792.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 26, 2014, 07:03:21 PM
Hi

I had a good day in the shop today, its bank holiday Monday and as usual it rained so we decided not to go anywhere. I set the base up in the mill and cleaned up all the sides with a fly cutter.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04604_zps74fd3aee.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04604_zps74fd3aee.jpg.html)

The handwheel is recessed for the nut.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04608_zpsbacaccf0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04608_zpsbacaccf0.jpg.html)

I was going to make a handle for the hand wheel when I came across this very nice chrome plated one. At less than £5.00 it wasn't worth making one.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04613_zps81b5351d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04613_zps81b5351d.jpg.html)

Drill and tap a 6mm hole

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04616_zpsfe640e11.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04616_zpsfe640e11.jpg.html)

And try it

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04617_zps713b6122.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04617_zps713b6122.jpg.html)

I have bored and reamed a .5 hole through the centre of the table for locating things so I have now drilled and tapped 6mm the centre of the spindle which will be useful for bolting things down

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04620_zps693781f1.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04620_zps693781f1.jpg.html)

The table is mounted in the mill and has all the degree markings applied, this took about an hour

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04622_zps439d3b21.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04622_zps439d3b21.jpg.html)

Then stamp in some numbers. I did this free hand in the end. I pondered for a while on how to make a jig to hold the stamps but decided it wasn't worth the effort.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04628_zps1c8de302.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04628_zps1c8de302.jpg.html)

And finally today I started on the table clamps. A bit of 25mm X 15mm steel bar is machined down to fit in the table groove. It needs a radius so I gestimated this and did it on my 6" grinder.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04634_zpsa26c71fc.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04634_zpsa26c71fc.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04636_zpsf331b950.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04636_zpsf331b950.jpg.html)

Cheers

Rich 
Title: Re: Building a 7" rotary table
Post by: Don1966 on May 27, 2014, 12:39:02 AM
That' some nice work Rich. Still following you bud.


 :popcornsmall:

Don

Title: Re: Building a 7" rotary table
Post by: Firebird on May 27, 2014, 01:29:06 PM
Thanks Don.

I do believe I'm getting somewhere now with the end in sight :Lol:

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on May 31, 2014, 08:41:01 PM
Hi

I finished making the two table clamps now I needed two bolts. I have used two 5/16 whitworth socket head bolts cross drilled 3/16. To make the handles I cut two lengths of 3/16 stainless steel. To make the ball ends I have used two 3/8 steel balls. These are soft not hard like ball bearings and can be drilled and machined easily. They are used as catapult ammunition.

Held in a 3/8 collet drill 3/16 just over half way.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04649_zpsaea162b2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04649_zpsaea162b2.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04651_zpse3db7575.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04651_zpse3db7575.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04655_zpscfa4efe8.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04655_zpscfa4efe8.jpg.html)

In the brazing hearth the two balls are silver soldered to the bar

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04660_zps72896a08.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04660_zps72896a08.jpg.html)

After a clean up the parts are blacked.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04669_zps41aa6835.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04669_zps41aa6835.jpg.html)

Drill and tap two corners 5/16 whitworth.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04678_zps90ee40c3.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04678_zps90ee40c3.jpg.html)

Make a key way for the spindle.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04661_zps9ab636d6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04661_zps9ab636d6.jpg.html)

And press in

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04666_zps83ddc919.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04666_zps83ddc919.jpg.html)

The spindle is assembled with hand wheel, worm gear, eccentric, two bearings and a thrust bearing

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04680_zps9b66b0c9.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04680_zps9b66b0c9.jpg.html)

finally today I have given the base a lick of paint on 3 sides. The side which is used to mount the rotary table vertically I have left unpainted.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04682_zpse5629594.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04682_zpse5629594.jpg.html)

Cheers

Rich

Title: Re: Building a 7&quot; rotary table
Post by: ths on May 31, 2014, 10:59:01 PM

  They are used as catapult ammunition.

As much as I've loved following this thread, and as impressive the just about finished product is, I really need to see this catapult.

But seriously, fantastic work.

Cheers, Hugh.
Title: Re: Building a 7" rotary table
Post by: Firebird on June 01, 2014, 05:30:26 PM
Hi

Thanks Hugh but sorry no catapult. You can buy these steel balls off ebay really cheap. These were £3.89 for 100 including postage.

Well its time to start assembling the rotary table. Fit the eccentric bush and pack the bearing with grease.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04685_zps2dd744b0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04685_zps2dd744b0.jpg.html)

I have made a large washer from plastic to cover the bearing, it sits around the spacer washer

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04689_zpsb91dfe01.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04689_zpsb91dfe01.jpg.html)

Followed by the adjuster nut. Adjust until there is no play and tighten the clamp bolt.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04693_zpsfbb7f043.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04693_zpsfbb7f043.jpg.html)

Fit the key into the keyway

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04694_zpse47b58d6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04694_zpse47b58d6.jpg.html)

Followed by the gear and its locking nut, then slip in the spindle, eccentric and worm gear.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04700_zpsc6f5d840.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04700_zpsc6f5d840.jpg.html)

Turn it over. The table had 4 6mm tapped holes which were used for mounting to the face plate when turning. Drill them right through 1/4" and fit 4 button oilers.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04701_zps711dfcfa.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04701_zps711dfcfa.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04702_zps0882d0b5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04702_zps0882d0b5.jpg.html)

Things are rolling along nicely............UH OH  :facepalm: take it apart again. I forgot to drill and tap a hole in the eccentric  :facepalm2: for the lever.

Drill and tap 3/16 X 40

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04707_zpsd2c31097.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04707_zpsd2c31097.jpg.html)

Thread a bit of 3/16 stainless steel round bar 3/16 X 40 and screw in.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04710_zpsc7ef771a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04710_zpsc7ef771a.jpg.html)

Everything turns well and freely, no tight spots.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Don1966 on June 01, 2014, 06:11:08 PM
That' nice work Rich and you have something useful and you built it. Isn't it a good feeling? Are you putting T slots in it?

Don
Title: Re: Building a 7" rotary table
Post by: Firebird on June 01, 2014, 06:25:18 PM
Hi Don

Yes I intend to put T slots in. I figured a size that will take 8mm studs looks about right. Then I looked round at what I have. My X1 mill uses 6mm studs, a bit small, and my X3 mill uses 10mm studs, a bit big.  :thinking: I think I will go with the 6mm as I already have all the T nuts and studs that I need. I can always open it out to a larger size later if I have to.

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: NickG on June 02, 2014, 08:19:32 PM
That is superb Rich! Yeah 6mm makes most sense then.
Title: Re: Building a 7" rotary table
Post by: Firebird on June 08, 2014, 01:53:52 PM
Hi

Thanks Nick.

I have ordered a T slot cutter, from china, so I have to wait for that to arrive. I don't know what the quality will be like but at les than £6.00 including the postage its worth a go.

I have had to make a little spacer to use when the rotary table is mounted vertically. The edge of the table just catches, it was ok until I fly cut the sides.

A bit of 4mm ally, a bit of 3/16" X 1/2" X 3" steel and a couple of 5mm countersunk socket head screws.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04712_zpsf18ef2b0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04712_zpsf18ef2b0.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04716_zps844212e0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04716_zps844212e0.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04718_zpsa1d53883.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04718_zpsa1d53883.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04721_zps809d0b8e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04721_zps809d0b8e.jpg.html)

This is the table with the clamps fitted

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04729_zpsc439b55d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04729_zpsc439b55d.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04732_zps4517709f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04732_zps4517709f.jpg.html)

I have made a little gadget to centre the table in the mill. A quick turning job. Turn down accurately to 1/2" to fit the hole in the centre of the table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04734_zps093df1a2.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04734_zps093df1a2.jpg.html)

Part off and hold in a 1/2" collet. Face and centre drill.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04737_zps98216f62.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04737_zps98216f62.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04738_zpsba217ddf.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04738_zpsba217ddf.jpg.html)

Drop it into the table

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04742_zps3a863655.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04742_zps3a863655.jpg.html)

Bring down a centre point and square with a set square

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04747_zps77c903d0.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04747_zps77c903d0.jpg.html)

Clamp the table down, lock the X and Y tables and zero the dials, easy

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Kim on June 08, 2014, 04:41:30 PM
Hi Rich,
I've been quietly following along with your RT build.  This is a nice piece of equipment you've built here! You should feel really good about it!  Congratulations on some great work!

Do you have anything else to go besides the T-slots?
Kim
Title: Re: Building a 7" rotary table
Post by: Firebird on June 08, 2014, 04:47:16 PM
Hi Kim

Thanks  :ThumbsUp:

No that will be about it for the table. There are a couple of bits of tooling I have in mind one being an adapter that takes the Myford screw on chucks but they will be made as and when I need them.

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Firebird on June 13, 2014, 07:57:19 PM
Hi

The T slot cutter arrived today

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04749_zps8933412f.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04749_zps8933412f.jpg.html)

I have never used one before so any tips would be welcome

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Jo on June 13, 2014, 08:00:38 PM
Slow and steady, get (vacuum) the chips out, you should not have any problems, it is not a difficult job  ;)

Jo
Title: Re: Building a 7" rotary table
Post by: Firebird on June 14, 2014, 01:16:16 PM
Hi

Thanks Jo.

Do you mean a slow cutter speed ?

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Stuart on June 14, 2014, 01:28:51 PM
Rich

If the. Table is CI. Then do not let the cutter rub it's the same for steel

As Jo said think how fast you would run a cutter of the same OD

I would run a normal slot mill in first to full depth then follow up with the the tee slot cutter but run it a smidge up from the bottom of the slot , it should not rub on the end , it's the same with a dovetail cutter do not cut on the end and side at the same time or tears will be shed

I fully endorse Jo use of the vacuum to keep the slot clean

If it gets blunt you can with care touch them up on a grinding wheel

Stuart
Title: Re: Building a 7" rotary table
Post by: Firebird on June 14, 2014, 01:51:32 PM
Hi

Thanks Stuart. Its fathers day tomorrow and when asked by my 3 lovely daughters what I would like to do I said spend the whole day in my shed alone. Well if thats what you want they said. Oh and a chinese take away for the evening meal would be nice. And of course  :DrinkPint: :DrinkPint: :DrinkPint:

So hopefully tomorrow I wil cut the T slots

Cheers

ricc
Title: Re: Building a 7" rotary table
Post by: Jo on June 14, 2014, 05:56:10 PM
Sounds like you have tomorrow made for you  :ThumbsUp: (I also like Chinese, nice change from curry  8) but its Saturday so its Sirlion  ;D)

I agree with Stuart (a couple of cuts to) take the centre to full depth with a slot mill first, don't worry if it goes slightly deep on one or another. Most tables you buy are not perfect when you look at the slots, you don't even have to get the tops of the slots spot on  ;)

Jo
Title: Re: Building a 7" rotary table
Post by: Don1966 on June 14, 2014, 09:33:52 PM
Hi Rich, I agree with Jo and would add to slow your spindle speed also to where the cutter is warm to the touch. It will cut the full slots and stay the same temperature when you have the right speed.

Regards Don


Title: Re: Building a 7" rotary table
Post by: Firebird on June 15, 2014, 04:50:09 PM
Hi

Well I'm pleased to say that the T slot cutting went well.

One little job to do first. I forgot to scribe in some pointers for the hand wheel and table so I got my mate Julian to print me a couple. He has aneat little lable printing gadget that prints into a plastic type ribbon

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04751_zpsce1ec73e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04751_zpsce1ec73e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04753_zps06532948.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04753_zps06532948.jpg.html)

With the table at zero and the handwheel at zero I cut the first slot with a 8mm cutter. This is a solid carbide cutter that I picked up at a show and cuts beautifully. You can see on the DRO I have cut to a depth of 12mm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04756_zps65a380d7.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04756_zps65a380d7.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04760_zps06d601d5.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04760_zps06d601d5.jpg.html)

With all 4 slots cut it was in with the T slot cutter, nice and steady.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04766_zpse471fe09.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04766_zpse471fe09.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04770_zpsa415f301.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04770_zpsa415f301.jpg.html)

I have drilled and tapped the table 4mm

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04772_zpse1ed8d0a.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04772_zpse1ed8d0a.jpg.html)

Turned and bored a sleeve that fits the central locating hole

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04776_zps58d8a8f6.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04776_zps58d8a8f6.jpg.html)

Which takes the myford threaded adapter

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04778_zps4f96b10e.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04778_zps4f96b10e.jpg.html)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04779_zps76e66257.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04779_zps76e66257.jpg.html)

With a myford chuck screwed on

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC04782_zpsb274874d.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC04782_zpsb274874d.jpg.html)

Cheers

Rich
Title: Re: Building a 7" rotary table
Post by: Jo on June 15, 2014, 06:11:04 PM
 :whoohoo:

So what are you going to make on it  :naughty:

Jo
Title: Re: Building a 7&quot; rotary table
Post by: NickG on June 15, 2014, 07:57:45 PM
Brilliant Rich, looks v professional.
Title: Re: Building a 7" rotary table
Post by: Firebird on June 15, 2014, 08:06:04 PM
Hi

Thanks Jo and Nick

Hopefully this current bout of tool making is over and I can get back onto my portable engine.

I would like to thank every body that has helped with this build, new skills had to be learned and I couldn't have done it without you.  :ThumbsUp:

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: ths on June 15, 2014, 08:50:16 PM
That's great Rich, does it have a horizontal mounting face on it?

Cheers, Hugh.
Title: Re: Building a 7" rotary table
Post by: tvoght on June 16, 2014, 05:37:33 PM
The table looks great Rich.

 I made a spindle thread mount for my rotary table so that I could use my Taig chucks on it.  What I found was that when machining outside diameters, the cutting forces were such that they unscrewed the chuck. Is that something you've thought of or planned for?

--Tim
Title: Re: Building a 7" rotary table
Post by: Firebird on June 16, 2014, 07:56:34 PM
Hi

Hugh, yes it does have a face for mounting the table vertically. If you go back to page 12 you will see I had to make a thin spacer to lift it clear.

Tim, yes I came across that problem when I had a myford adapter in my 4" table. I drilled and tapped the chuck backplate 6mm through the boss and fitted a pointed grub screw. With the chuck screwed  tightly onto the adapter I drilled a dimple into the thread of the adapter. Tightening the grub screw into the dimple solved the problem. I don't use the grub when the chuck is on the lathe, I don't want to damage the lathe spindle. I can use the same method on this table.

Cheers

Rich
Title: Re: Building a 7&quot; rotary table
Post by: ths on June 16, 2014, 09:00:08 PM
Yes I found that, thanks Rich. Hugh.
Title: Re: Building a 7" rotary table
Post by: RichardHed on October 22, 2021, 01:38:01 PM
Hi

One of the best things I have done is to fit a 4 jaw independant chuck to my vertex 4" rotary table.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03661_zps5182e1ba.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03661_zps5182e1ba.jpg.html)

Setting jobs up in the mill is easy and very accurate using a DTI. It's so useful that I'm reluctant to remove it when other jobs come up. What I could do with is another rotary table.

Have you seen the price of these things now  :rant: :rant:

It was a big expense when I bought mine about 6 years ago but they have about doubled in price, beyond my pocket now.

Plan B.   Can I build one  :noidea: I remembered seeing Arnold build one so I dug back and found his build and have just finished reading it, excellent Arnold  :praise2: :praise2:

I'm going to have a go at something around 7". Like Arnold I have started by throwing a few bits on the bench.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC03664_zpsd6300930.jpg) (http://s242.photobucket.com/user/firebird_021/media/DSC03664_zpsd6300930.jpg.html)

Some 50mm x 15mm steel bar, a gear, origin unknown but big enough to get a 7" table and thick enough to cut T slots if I wish. Some brass rings for the worm wheel, a bearing and a bit of 1/2 steel plate.

This will be one of those projects that lies on the bench and gets worked on every now and then so don't expect any rapid results  ;D ;D

Cheers

Rich
Do you have prints for the 7" rotary?  I am building one, but I have to make drawings.  It would be easier if the drawings already existed.  Actually, the one I am making is 6", but I prefer a larger one.

Richard
Title: Re: Building a 7" rotary table
Post by: Firebird on October 22, 2021, 08:21:44 PM
Hi Richard

Sorry no drawings. I sort of made it up as I went along

Cheers

Rich