Author Topic: Myford 7 Carriage Handwheel Dial  (Read 7693 times)

Offline Bjorn_B

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Re: Myford 7 Carriage Handwheel Dial
« Reply #15 on: February 15, 2016, 05:35:05 PM »
Guys,

Thanks for the comments.

AS,

Yes , it really is as simple as it looks


I'm over-complicating things... Lesson to be learned here

Sewing machine motor?

Offline Allen Smithee

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Re: Myford 7 Carriage Handwheel Dial
« Reply #16 on: February 15, 2016, 05:57:47 PM »
Thanks for that, Rod.

I'm thinking more along the lines of using a drill-chuck, largely because I have a few spare ones and I don't really want to stock another range of collets and most of the use I can see for the thing is for indexed drilling rather than milling. So I'm pondering around a 12mm shaft with a J1 taper on the end, or perhaps a Morse 1 socket with an adaptor arbor so I can make one-of end-mill holders from blank-end arbors as I need them. Or perhaps an MT2 socket so I can use either my myford tailstock stuff or specials made from some black-end MT2 arbors which I happen to have

Actually now I think about it I have at least one quite good small drill-chuck that's on an M14x1 thread (from my unimat), so that would be another option to consider!

I'm not looking at a mains-powered sewing machine motor, but (again) thinking more along the lines of a 200w brushless motor with speed controller running from a simple DC power supply for a more compact solution.

Hmmm...too many options - more thought needed  :wallbang:

AS
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Offline Allen Smithee

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Re: Myford 7 Carriage Handwheel Dial
« Reply #17 on: February 17, 2016, 07:51:09 PM »
OK, so I've had a really hard think during the boring bits of a day-long meeting at the IET today. I've come to the conclusion that this would be a very useful device, but I will almost certainly only ever want it for drilling holes and spot-facing - this will also increase the priority on completion of the 90% complete GH Thomas Headstock dividing set that I have...

So I'm drawing up something similar using angular-contact bearings, with a shaft to carry one of the many standard drill chucks I have lying around. I'll find the one that looks the most concentric and use that! But I'll size it for 12mm bearings so that, should I decide I need a decent collet chuck on it at a later date, I can use something like the Arc ER11 plain-shank chuck that you mentioned Rod...

PDR
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Offline tangler

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Re: Myford 7 Carriage Handwheel Dial
« Reply #18 on: February 17, 2016, 08:20:14 PM »
ARC do an ER11 collet chuck with an internal JT1 taper, so if you can find a drill chuck with a JT1 taper...

You would probably only need one collet - 1/4" or 6mm for milling

Rod

Offline Allen Smithee

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Re: Myford 7 Carriage Handwheel Dial
« Reply #19 on: February 17, 2016, 11:21:04 PM »
Now you've gone and done it again! I was intending to do the spindle as either M14x1 male (to suit the chuck I have on the tailstock of my unimat 3) or a femal thread which I think is 3/8-BSF to suit the threaded stub on two old drill chucks I have lying around (I think they're prehistoric black & decker).

But it looks like I'm going to have to bite the bullet and turn a JT1 taper on the end of the spindle and get a JT1 chuck to suit it so that I have the option of the ER11 collet if I change my mind. I suppose if I turn the 12mm shaft and JT1 taper in one set-up at least I'll be getting minimal run-out in the chuck.

It was all so simple while I was doodling in that meeting!

Anyone got any clever tricks that make turning a 2.2074 degree taper  as simple just-do-it thing?

 :smokin2:

AS
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Offline Steamer5

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Re: Myford 7 Carriage Handwheel Dial
« Reply #20 on: February 18, 2016, 01:51:50 AM »
Hi Allen,
 Don't you just hate it when your to do list jumps in size! I've got a project requiring a taper to be turned also......an ER 32 collet chuck for my Emco lathe.....anyway had an idea, First set the tool post square to the top-slide by what ever is your favorite method, currently mine is using a 1,2,3 block, loosen the top-slide so it can be rotated, set your digital or whatever pro tracker to the required angle, hold against the chuck & set the top-slide to it, now how to set it to the parts of an angle I'll leave to you to tell us!
 
Rod,
  That turned out really nice! Thanks to Grey for the design.

Cheers Kerrin
Get excited and make something!

Offline Graham Meek

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Re: Myford 7 Carriage Handwheel Dial
« Reply #21 on: February 18, 2016, 09:46:52 AM »
Hi AS,

Have you considered making the spindle nose the same as the collet holder?

If I remember correctly the collet taper is a plain 8 degrees. If you make the spindle nose larger you would be able to go for a larger collet. Having a larger collet allows the manufacture of a special blank collet but with a JT taper, or internal thread, or external M14x1P thread to take a drill chuck. The only problem is you would need a dedicated collet closing nut for the drill chuck, unless the drill chuck is easily detached. OR why not just put a plain arbor on the drill chuck and grip it in the larger collets, this way you do not need the extra collet closing nut. It all depends on how accurate you need the set-up to be.

Just a thought!

My best regards
Gray,

Offline Allen Smithee

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Re: Myford 7 Carriage Handwheel Dial
« Reply #22 on: February 18, 2016, 01:11:02 PM »
Thanks for your thoughts, chaps. My usual problem with something like this is simply that I start with a concept for something that will do things I want to do, but within minutes this expands into all the possible things it COULD do (most of which I will never actually need), resulting in a set of requirements that define a design of a hundred times the complexity and/or precision which is such a challenge to make that I never actually do it!

So I've set myself some boundaries. First on the operational requirement:

1. I want to do be able to drill off-axis holes in the lathe, using my currently unfinished GHT headstock indexing/dividing attachment (so that needs to be finished as well).

2. The holes will all be axial (parallel to the spindle axis) so that the unit [held in a milling slide] can be mounted directly on the myford cross-slide "boring table" (not on the compound or the toolpost). The milling slide I'll be using will be this one:



3. Whilst drilling radial holes (90 deg to the spindle axis) might be useful I won't make specific provision for it. I already have some capability in that area because I can mount the mill/drill head from my Unimat 3 dorectly on the myford's cross slide, and anything that needs more than that can be done in my Seig X2p using my rotary table or my VDH (when I finish it - can you see a pattern emerging here?).

4. I want to be able to use drills and possibly reamers from "small" up to about 6mm/1/4" because I don't think the setup would be stiff enough to go much bigger, and this bounds the chuck size. This means I'm looking at spindle speeds in the range 200-6,000rpm, which means it needs ball-races rather than plain bearings. I'm assuming angular contact bearings to minimise the risk of chatter. The only milling capability I want to treat as a primary requirement is the use of slot drills to spot-face and/or counterbore to get flat seats for screws and nuts. This means that I'm probably going to get what I want from a drill chuck rather than needing collets.

5. Whilst being aware that at these speeds I could have some "toolpost grinding" capability it's not something I want to make particular provision for because I don't like grinding in my lathe (the shear amount of work involved in covering and protecting everything and then cleaning down afterwards).

6. Sewing machine motors are OK, but they are expensive and bulky for what they are, so I'm going to try using a cheap brushless motor operating from a 12-18v DC power supply at around 200watts. I've mentioned this before and have a bunch of suitable candidates in my spares boxes, so this is the opportunity to find out if it really does work. If it does this would make for a much simpler/cheaper solution to powering things like the UPTs

7. I happen to have a mild steel block which is 82mmx46mmx46mm that is almost exactly the same width as the milling slide. I think the 82mm dimension would be long enough to give decent support to the spindle, so this looks like the candidate chunk of metal to make it from!

AS
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Offline Allen Smithee

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Re: Myford 7 Carriage Handwheel Dial
« Reply #23 on: February 19, 2016, 11:07:20 AM »
Rod,

I apologise - I've diverted your thread. I'll stop and start a new one. Please feel free to send your gamekeeper around to give me a sound horsewhipping!

AS
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Offline tangler

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Re: Myford 7 Carriage Handwheel Dial
« Reply #24 on: February 19, 2016, 12:06:16 PM »
No probs.  It had already run its course.

Rod