Author Topic: Levelling the Lathe - an adventure  (Read 1243 times)

Offline Joco

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Levelling the Lathe - an adventure
« on: August 01, 2017, 09:02:31 AM »
After getting the lathe mobile I was able to also get it under the block and chain and remove it from the stand. The intent being to continue my checks of the setup in the quest of getting a well tuned lathe capable of turning very parallel work.  Something it is not doing to the level I would like.

So first off lathe removed.  Nothing special here but a bit of gratuitous "block and chain".   :naughty:



After that the drip tray was removed and so were the adjustable feet.  Things felt pretty dang flat.  There was a very very minor amount of movement in the stand and just putting a single playing card (an Ace of Spades from memory) under any leg made things worse. Like I said, pretty flat.   Anyway from here I started assessing how flat things were across the top struts that the lathe is actually bolted to.  I dont have a super accurate engineers level so this is done using a long level I had from a DIY work around the house.

Top view of the lathe stand for reference to help visualise the different dimensions being assessed with the level.



Each the of the different checks:








Having looked as these checks and I would say that the stand is actually pretty dang level. Nothing that a small amount of shiming under the lathe feet would solve at any rate.  On the plus side my welding and fabrication was clearly better than I thought as I was convinced there was a bad twist somewhere.

The next problem to investigate is how the chip tray is sitting.   The suspicion is that the amount the cross supports are raised is not quite enough to esnure that the drip tray is not actiing a bit like a spring.  This isn't an issue at the Head Stock end but given the Tail Stock is much closer to the edge and therefore the spring effect I think that might be having an alignment impact. Results of the investigation in the next post.

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #1 on: August 07, 2017, 12:27:57 AM »
A brief pause while I sort out a better drip tray on the stand that should make flood coolant a little easier to setup. ie less work in trying to seal the existing stock tray.
James
Wellington - NZ

Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #2 on: August 13, 2017, 04:41:11 AM »
Okay we are back.   The drip tray is pretty much done and the paint is drying so while that happens I have gotten the lathe back on the stand and its all levelled up. This time no rubber pads under the levelling feet.  I also squared the base of the feet to the bolt in the mill.  Especially after re-welding them so they would be very unlikely to break again. 



I then embarked on an exercise to true things up using Rollie's Dad's method.  I know there are lots of discussions on how good or not good this approach is but it seemed to make sense, I had the tools to try so what the heck.   :popcorn:

I had some round bars that were rollers from a printer or photocopier (thanks Bruce!) one of which I used as the test bar.  Setup the 0.01mm test indicator and off we went.

Here are screen shots from the spreadsheet I used to track the numbers for the horizontal then vertical tests.




From these you can see the horizontal was pretty much on the money right from the start. The delta was very small and while I could have gone for even higher accuracy I actually don't have anything that measure better than 0.01mm.

The vertical needed a bit of work.  I started putting shims under the tail and no noticeable improvement in fact things started to get worse.  So I removed those shims (0.1mm thick aluminium from soda cans). I then put a set under the headstock end.  Since this "foot" is rather large and covers two support beams this means 4 shims in total.


This moved the delta to 0.03mm.  I decided that didn't seem too bad so decided it was time to cut a test parallel.   So to control over hang I took some ~19mm round bar and took some cuts over 100mm length using power feed to get a really consistent surface.   The moment of truth ...
Measuring the tail end.


Measuring at the head stock end.


BINGO! Cutting parallel.  Well at least within the limits of my 0.01mm callipers.
 :whoohoo:   :pinkelephant:   :cartwheel: 

Cheers,
James.
« Last Edit: August 13, 2017, 07:05:22 AM by Joco »
James
Wellington - NZ

Offline Chipswitheverything

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Re: Levelling the Lathe - an adventure
« Reply #3 on: August 13, 2017, 08:38:26 AM »
Very nice stand that you have made, and your result of shimming and the trial cut is very satisfactory.    But I'm a little puzzled here, won't you have to lift the machine and reset things when the drip tray is put on the base? - and is the lathe in it's final resting place in the workshop?   Dave

Online steamer

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Re: Levelling the Lathe - an adventure
« Reply #4 on: August 13, 2017, 01:16:27 PM »
Nice work Joco!   the biggest objective to leveling a lathe is to take the twist out of the bed.   Looks like you've done that.   I might suggest that when you get a micrometer, you check it further.

Dial and digital calipers are good to about +/- 0.05mm honestly...regardless of how many digits are showing....but you are close!

Check it periodically for the next couple of weeks...sometimes they settle and move a little.

Dave
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Offline Mosey

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Re: Levelling the Lathe - an adventure
« Reply #5 on: August 13, 2017, 01:53:15 PM »
I respectfully suggest you check it every few months, as it is sitting on a concrete slab on the earth. The earth under it moves with the seasons from moisture changes. Also, a Starrett or other quality brand machinists level will be worth the $50.00 Ebay or so to get better leveling and you'll use it over the years.
Mosey (Still kicking, Eric)

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Re: Levelling the Lathe - an adventure
« Reply #6 on: August 13, 2017, 03:06:57 PM »
I respectfully suggest you check it every few months, as it is sitting on a concrete slab on the earth. The earth under it moves with the seasons from moisture changes. Also, a Starrett or other quality brand machinists level will be worth the $50.00 Ebay or so to get better leveling and you'll use it over the years.
Mosey (Still kicking, Eric)

Yes a series 98 level would be a great addition...but I'd get the micrometer first....

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #7 on: August 13, 2017, 08:57:53 PM »
Nice work Joco!   the biggest objective to leveling a lathe is to take the twist out of the bed.   Looks like you've done that.   I might suggest that when you get a micrometer, you check it further.

Dial and digital calipers are good to about +/- 0.05mm honestly...regardless of how many digits are showing....but you are close!

Check it periodically for the next couple of weeks...sometimes they settle and move a little.

Dave

Dave - yes its in the final place.  My "workshop" is actually my half of the garage.  The boss expects to get her car back in there and is making some strident noise to that effect.

As to the drip tray, I have "dumped" the factory one for a custom config inspired by the configuration of a mates new AL336. See this thread on how that will look http://www.modelenginemaker.com/index.php/topic,7341.0.html

A 0.001mm mic is on the "really want one of those" wish list.   It will probably not be digital as they seem to be quite pricey in comparison to the analogue version.

Cheers,
J.
James
Wellington - NZ

Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #8 on: August 13, 2017, 09:01:14 PM »
Steamer/Mosey - yes checking it periodically for seasonal shift and settling is a good idea.

An engineers level would be nice to have but as Steamer noted I think I'll slump up the $$ for the mic first.  It will get more general use.

Cheers,
J.
James
Wellington - NZ

Offline zeeprogrammer

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Re: Levelling the Lathe - an adventure
« Reply #9 on: August 13, 2017, 11:37:44 PM »
I hope I'm not hijacking here...

Since I'm about to get a new lathe, I'm interested in the discussion on leveling.

I understand the need to take twist out. What I don't understand is whether it matters if one end is higher/lower than the other.
All is still square with each other no?

Thanks.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you', whistles, and certain dinner bells.
"Found a peanut."
To work. To work. Zee-The Thread Trasher.

Online steamer

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Re: Levelling the Lathe - an adventure
« Reply #10 on: August 13, 2017, 11:47:04 PM »
The only thing that really matters is the twist...if the bed is slanted it doesn't matter    twist is the issue.    That said the easiest way to get the twist out is to level it in all planes.
"Mister M'Andrew, don't you think steam spoils romance at sea?"
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Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #11 on: August 13, 2017, 11:58:30 PM »
Carl - as noted it's all about being aligned down the bed. The actual relationship of the bed to gravity level is immaterial.  Consider that large ships, particularly military ones, will have a machine shop with lathes, mills etc in them and they are never constant to gravity level, even when in port there will be slight movements.

However as also noted getting the lathe level in relation to gravity just makes for an easier starting point. The more accurately you can achieve this the better starting position you will be in.

While an engineers level that is able to show very small changes over a long distance would be ideal you can do a pretty good job using a tradesman class level followed by some form of test bar process.  I used the "Rollie's Dads" method but there are other approaches.

Cheers,
James.
James
Wellington - NZ

Online steamer

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Re: Levelling the Lathe - an adventure
« Reply #12 on: August 14, 2017, 01:12:15 AM »
The cool thing about Follies dads method is it allows you to adjust for wear.   
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Offline Steamer5

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Re: Levelling the Lathe - an adventure
« Reply #13 on: August 14, 2017, 04:13:12 AM »
Hi James,
 Well done! Now I've got another job on my list! Ah well, SWMBO hasn't come up with anything yet this week......

Mossey,
 In this part of the world it's not the moisture in the earth under the concrete that's the problem, it's when the earth decides it's had enuff of sitting still for a couple of millennia & moves UP 4 or 5 meters, OR sideways 8 OR 9 meters that the fun begin's,!

Cheers Kerrin
Get excited and make something!

Offline Joco

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Re: Levelling the Lathe - an adventure
« Reply #14 on: August 14, 2017, 06:16:14 AM »
James
Wellington - NZ

Offline Chipswitheverything

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Re: Levelling the Lathe - an adventure
« Reply #15 on: August 14, 2017, 01:52:07 PM »
James, I've got a Mitutoyo digital mike which I bought a few years ago at a show, thought I'd modernise a bit.  But though I often take it out of the box and admire it, and it works very well, time and again it stays in the box while I use one of my ordinary traditional mikes, M&W, Starrett and so on.  The reason is, the digital mike just doesn't fit into the hand in the way the older mikes do, so that it is always a two handed operation to check a measurement:  and also, when you are done measuring at the machine, the thing wants a bit more care in putting down among the workshop debris.   So in the end, I just reach for the simple mike that has served me all these years...   Dave

Offline zeeprogrammer

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Re: Levelling the Lathe - an adventure
« Reply #16 on: August 14, 2017, 05:13:49 PM »
Thanks for the help all.

And the point about lathes being on ships gave me a 'doh' moment.  ;D
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you', whistles, and certain dinner bells.
"Found a peanut."
To work. To work. Zee-The Thread Trasher.

Online steamer

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Re: Levelling the Lathe - an adventure
« Reply #17 on: August 14, 2017, 07:57:48 PM »
Check here.   Lathe for use on a battleship
http://www.lathes.co.uk/leblond/index.html
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Online Vixen

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Re: Levelling the Lathe - an adventure
« Reply #18 on: August 14, 2017, 08:40:51 PM »
Dave,

When you install a lathe on a ship, some say it's best to align the bed fore and aft, the pitch motion is always less than the roll. However, we did the opposite, If you are working in rough conditions, the lathe operator standing so as to face fore and aft, was less likely to sway into the revolving machinery if the ship rolled unpredictably.  It's your choice, safety or precision.
Another very useful modification is to fit some sort of end stop to prevent the tail stock sliding off the end of the bed if some idiot forgets to lock it tight to the bed. Makes one hell of a noise when it falls onto the steel deck plates in the middle of a stormy night.

Been there

Mike
« Last Edit: August 14, 2017, 09:11:32 PM by Vixen »
It is the journey that matters, not the destination

Offline Mosey

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Re: Levelling the Lathe - an adventure
« Reply #19 on: August 15, 2017, 02:39:05 PM »
Check here.   Lathe for use on a battleship
http://www.lathes.co.uk/leblond/index.html

Perfect for the compact home shop. Economical and where can I order one?
Mosey

Offline Dan Rowe

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Re: Levelling the Lathe - an adventure
« Reply #20 on: August 15, 2017, 04:34:48 PM »
Thanks Dave that is a very scary concept wheels on a ships lathe. It not really all that handy to be able to move the lathe on a ship. You still have to plug it into something and even if the wheels had locks they could slide. Now I hope I can forget about that crazy idea.

I ran quite a few ships lathes and even a large LeBlonde and most of them were fore and aft one or two went the other way but every one of them was BOLTED to the deck.

Dan
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Online Vixen

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Re: Levelling the Lathe - an adventure
« Reply #21 on: August 15, 2017, 04:49:42 PM »
Dan,

When I worked for the oil industry out in the North Sea it could get pretty wild at times. The seas were big and our ship was small. We had a Boxford lathe bolted securely to the deck, mounted side to side.
When the weather was too rough for us to ,launch the two man submersible, we stood down and had some free time to ourselves, time to go and make something. Today's Elf and safety people would have a blue fit at the thought of running a lathe in conditions where you could not stand without holding on.  But back then, we were young and invincible; it would never happen to us.

Mike
« Last Edit: August 15, 2017, 04:56:26 PM by Vixen »
It is the journey that matters, not the destination