Lathe bench help

lazyLathe

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Hi All,

Over the past month i have been busy trying to set up my latest acquisition, a Myford ML7. ;D
It is in really good condition and came with a few attachments and bits and bobs.

I was given an old steel bookshelf from work that i cut the top off to get it to a reasonable height.
I left all of the bracing and supports in the bookshelf for extra strength.
Added a top of hardwood that was sandwiched between two 1mm steel sheets.
All looks good and i thought it would do the job admirably.

BOY, was i mistaken... :(

It seems that the "hardwood" is not that hard after all...
After levelling and shimming using a machinists level i go to bolt it down securely to the top.
This is done slowly while checking the level to make sure it stays in the same place all the time.

The when i use my MT2 test bar to test the vertical and horizontal alignment it is out by quite a bit.

I am wondering what to do to try and get rid of this problem.
I know a lot of people use wooden benches and have no issues.

So i am thinking of buying a pretty hefty size metal sheet to use for the top.
Something really sturdy to bolt the lathe onto that will not deform or deflect under stress.
Any ideas on what thickness to use? I would also like to stay in a reasonable price range....
I do not have the equipment to drill through very thick steel and i need to be able to carry and lift it by myself.

I have attached some pictures of the unit i built as it may help to bring in some more ideas.

Any help or ideas on what i can do to improve the situation would be greatly appreciated.
This is my first large lathe, the one before this was a long bed Sherline so it was not that big of an issue.

Thanks,

Andrew

P1010541.JPG P1010540.JPG
 
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My recommendation is to let the lathe float. The bed is rigid enough on it's own to give you good service. Even bolting a machine to a concrete floor is not always the best solution. In your case, there is nothing to be gained by trying to marry the lathe to the bench. Once the bench is level and flat, use some cushioning to isolate the lathe from any distortion that the mounting bolts might induce. If you have a bench made of a solid steel top on heavy steel legs, and it is bolted to the floor, then you might be able to satisfactorily mount the lathe firmly to the bench. After that, any movement in the floor or the bench would need to be compensated for in the machine mounts.
 
Being a newbie to this, i must be missing something...

There is a lot of conflicting information that i have been given on this topic.
So i am stuck in the land of confusion for the moment.

If the bench is level and flat according to the level and if the lathe bed has a slight twist in it, how would i get rid of the twist.
Since i cannot bolt it down to get rid of the twist because the hardwood deforms to me it would be logical to mount it to a more solid top that
would not deform under the stresses of the bolts being tightened.

You mention to use some cushioning to isolate the lathe from any distortion induced by the mounting bolts.
Could i not remove this distortion by replacing the top with a solid steel platform?

I know i must be missing something in the picture but for the life of me i cannot see it.

I forgot to mention that i added levelling feet onto the bottom of the stand.
That is how i levelled the bench while the lathe was on it.

Sorry if i am asking crazy clear questions but at the moment the water is very muddy for me.

Andrew
 
My reasoning is this, Andrew. The wood top is not as rigid, nor can it be as strong as the bed casting. If there is a twist on the bed, it will pull the top into a twist, with only a little(very little) effect on the bed twist. If you have a solid steel top, it too will yield to the bed twist, to a lesser degree. You can get some twist out of the bed that way. Do you know the bed is twisted? Chances are that unless it has been mounted in a twist on a strong steel table, and for a long time, the little twist that may be there is insignificant. How are you planning on measuring this twist? If you choose a solid steel platform, you will you ensure that it is truly flat?

The idea of the isolation is to prevent influence of the probably not flat bench on the probably true bed. You also will gain vibration isolation using mounts.

No need to apologize. Ask away!
 
Thanks Tony!

My theory is very limited when it comes to mounting a lathe and getting it to turn parallel and not turn a taper.
I was thinking if i mount it to a solid surface i would be able to shim and adjust to get it straight.

what i did tonight was to change the top of the bench.
I removed the hardwood and replaced it with a man made material of composite resin and stone mix.
We used them for our countertops at work for many years and they withstood everything we could throw at them!

Step 1 - Shim the lathe till it is level all over the bed using a Starrett machinist level.
Step 2 - Tighten the four bolts slowly while checking the machinist level to ensure the bubble stays in the same place.
Step 3 - perform "Rollie's Dad's method" of checking the lathe.
To do this i have a MT2 taper test bar that is ground to 0.0002 tolerances.
Using my DTI i measure the vertical and horizontal at both the headstock and the tailstock.

These are my readings:
Horizontal-
Headstock = 0.0005
Tailstock = -0.0025 and +0.0005

Vertical -
Headstock = 0.0000
Tailstock = +0.0015 and -0.0015

So i am not sure if i am chasing perfection or if the reading i got are good enough??

It's all a bit confusing...... :eek:

Andrew
 
Unless the steel shelf is VERY heavy duty, I think you are going to be constantly annoyed by buzzing and vibration of the panels which, if bad enough, will end up affecting your finishes. I'm less worried about getting it perfectly level (enough tweaking will get you there) than the buzzing. Here is my cheap lathe stand solution. It's made from 3 surplus heavy duty office cabinets. After bolting them together (In a LOT of places) the assembly became VERY solid. I welded up a base frame and put an Ikea wood counter (about $80) on the top. I completely killed the buzzing I used to get from a craftsman workbench.
 
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