Lathe leveling - do you do it with the lathe fully dressed or just the headstock and ways?

[Richard King 2]

It looks as if it needs some diagonal supports like RJ suggests. Thanks for the new pictures. I thought those rubber pads were wheels. I have seen those rubber pads have issues in the past. Your pucks look good, but the the ones you buy are rated for PSI - I would take some test cuts and see what happens . That's a light machine and it may be fine. I always say better safe then sorry and over doing it is better...lol.. It just seems like more support on the base would be better. I like the jam nut levelers, might add some lock washers under the bottom lock nuts. I would not use plywood. You can buy a butcher block wood table top and use that if you want it sitting on wood. Plywood's name "PLY" means bend.

It is wonderful to see your "love" for the machine to make it right and share here with word and pictures.. A great example to the new Hobbyists who read the forum. Thank You!

 

[WobblyHand]

I've done the wood thing for benches and seen them sag. So not eager to do that again.

It just seems like more support on the base would be better.

What do you mean by this? Do you mean installing a 1/2" plate on top of the 1/4" plate, (running the length of the lathe) or something entirely different? I'm new at this, so don't understand what may be obvious to you.

I can source some 4" diameter, 1/2" thick steel rounds for the feet. I will also get some 1/8" x 1" steel for X braces. Anything else to beef this up? Greatly appreciate all the help I am getting here.

 

[RJSakowski]

One thing not mentioned is to not firmly bolt the lathe down. On a light lathe, the practice of firm mounting can introduce a twist to the lathe bed. The lathe can be secured with mounting bolts tightened finger tight with the nuts secured with a jam nut or LocTite to prevent vibrating loose. While this does nothing for adding the stand mass to the lathe mass for reduced vibration, it will isolate the lathe from issues caused by an inadequate stand.. In particular, if circumstances require use of wood base, it will isolate the dimensional changes of the base due to temperature and/or humidity fluctuations.

A quick test using the two collar method or Rollie's Dad's method will determine if this is satisfactory or not.

 

[WobblyHand]

One thing not mentioned is to not firmly bolt the lathe down. On a light lathe, the practice of firm mounting can introduce a twist to the lathe bed. The lathe can be secured with mounting bolts tightened finger tight with the nuts secured with a jam nut or LocTite to prevent vibrating loose. While this does nothing for adding the stand mass to the lathe mass for reduced vibration, it will isolate the lathe from issues caused by an inadequate stand.. In particular, if circumstances require use of wood base, it will isolate the dimensional changes of the base due to temperature and/or humidity fluctuations.

A quick test using the two collar method or Rollie's Dad's method will determine if this is satisfactory or not.

The bolts are tightened, but not firmly. Tightening a bolt through relatively thin wall tubing just isn't a good idea. Great way to collapse the tube. But I'll check the bolts and loosen them if necessary. Good idea on loctite.

Haven't gotten close enough to level (twist) to consider two collar or RDM. I can fiddle with it a bit and try RDM to see how far off I am. I have a 20mm ground shaft I could measure. There's some 2.5" aluminum stock for two collar test, if I can find where I put it.

 

[RJSakowski]

.... You don't tell us or show us how you have it attached to the frame. RJ must go into this. How about some close ups of how you have it. You can also do the final test using what is called the 2 - collar test, by taking test cuts on an 1 1/2" aluminum shaft. We can tell you how if you need it.

The 1/4 x 7" plate is entirely too flimsy for a consistent mount. The lathe uses just two bolts for mounting; one for the headstock and onr for the tailstock. Any attempt to bias the mounting with shims to correct a bed twist will distort the plate. This will cause an ongoing chasing your tail situation where any slight disturbance of the stand will result in a change in the lathe alignment.

My stand has a length of 7" channel which isn't much more rigid than the 1/4" plate/square tubing. My solution was to add pieces of heavy plate between the lathe and the stand. The plate is firmly bolted to the stand in four corners, transferring any forces to points mych closer to the flanges of rhe channel rather than the relatively flexible center of the web. Shimming to correct twist is then done between the rigid plate anf the lathe foot which causes any bias to be made by the lathe.

 

[RJSakowski]

The bolts are tightened, but not firmly. Tightening a bolt through relatively thin wall tubing just isn't a good idea. Great way to collapse the tube. But I'll check the bolts and loosen them if necessary. Good idea on loctite.

Haven't gotten close enough to level (twist) to consider two collar or RDM. I can fiddle with it a bit and try RDM to see how far off I am. I have a 20mm ground shaft I could measure. There's some 2.5" aluminum stock for two collar test, if I can find where I put it.

I would start with the RDM method for testing first. It's quicker than the two collar method and can be just as accurate if done properly. When everything looks good by that, do a final test via the two collar method for verification.

 

[WobblyHand]

The 1/4 x 7" plate is entirely too flimsy for a consistent mount. The lathe uses just two bolts for mounting; one for the headstock and onr for the tailstock. Any attempt to bias the mounting with shims to correct a bed twist will distort the plate. This will cause an ongoing chasing your tail situation where any slight disturbance of the stand will result in a change in the lathe alignment.

My stand has a length of 7" channel which isn't much more rigid than the 1/4" plate/square tubing. My solution was to add pieces of heavy plate between the lathe and the stand. The plate is firmly bolted to the stand in four corners, transferring any forces to points mych closer to the flanges of rhe channel rather than the relatively flexible center of the web. Shimming to correct twist is then done between the rigid plate anf the lathe foot which causes any bias to be made by the lathe.

Pretty sure I understand your first paragraph. To be honest, I'm a little slow in understanding your solution (2nd paragraph). I think there is a link to your thread in this thread. I will re-read it. Hopefully, I'll be able to understand it enough to formulate some more targeted questions.

 

[jwmelvin]

If you’re going to use the stand to twist the bed, the stand has to be rigid enough to apply those loads. RJ uses a channel and thick plate to provide a rigid support, and shims between that and the bed mounts to impart twist.

Your stand is attempting to support twist through the outer frame only. The inner structure to which the bed mounts will have to twist with the bed; so stiffness there is working against you when using the four outer bolts to impart twist.

I think you’d be better off doing like RJ and imparting twist by controlling between the bed and the support. Make the support as rigid as possible.

Alternatively, you could bolt the lathe to a separate plate under each end of the bed and use jack screws under each of those plates to impart twist. That makes it more easily adjustable than shims. Of course, you’d want to make the structure supporting the jack screws to be as rigid as possible. The current outer frame isn’t enough. If you were to use that approach, I’d support each plate with three jack screws to limit potential bending of the plate; I’d align one screw with the bed centerline and the other two along a perpendicular so that the latter two could control twist without touching the third. In this alternative approach, the plates themselves need to be somewhat rigid as they need to support the moment loads applied to each foot.

 

[WobblyHand]

My command of the terminology is a bit weak, so, please bear with me. The additional bolts at the top of the frame seen in post #30 can be adjusted to twist with respect to the frame. They effectively are jack screws. Now the 1/4" may be a bit flimsy, but there is some adjustment besides the feet. Is it better to have one long thick bar picking up the two bolts, or two independent (cross) bars?

I just got back from getting rid of a pallet, but I will read RJ's thread on the thicker plate. I'm a bit fuzzy on how RJ's plates were attached. I will have to solve the how do I lift the darn lathe when it is in a low basement problem, but first I need to understand a sufficient solution. I don't mind a little over-engineering, but whatever the solution is, I have to be able to implement it within my constraints. Hope that a little insight from smart folks like you can help relax some of the (self-imposed?) constraints.

 

[WobblyHand]

Alternatively, you could bolt the lathe to a separate plate under each end of the bed and use jack screws under each of those plates to impart twist. That makes it more easily adjustable than shims. Of course, you’d want to make the structure supporting the jack screws to be as rigid as possible. The current outer frame isn’t enough. If you were to use that approach, I’d support each plate with three jack screws to limit potential bending of the plate; I’d align one screw with the bed centerline and the other two along a perpendicular so that the latter two could control twist without touching the third. In this alternative approach, the plates themselves need to be somewhat rigid as they need to support the moment loads applied to each foot.

Can you elaborate on this? Understand the jack screw part. And the plate positioning relative to the lathe. What are you recommending for the reinforcement of the existing plate/tubing setup? Do you think any of this can be done "in place", with simple levering, or do I need to totally lift away the lathe? By each foot, what are you referring to?

This discussion is very helpful. Thanks for contributing.