Thread: lathe alignment

Originally Posted by casjon

I really don't think you have much of a choice here other than replacing the gap, the other options leave a little to be desired. If the Chinese managed to true it up, there is no reason why you can't. It's a bit like leveling, first time you do it it takes forever, after that it's pretty easy. It may take a little time but by the time you have finished you'll be an expert and you'll be able to tell us all how it's done, well most all of us anyway...

yeah ill eventually get to it, want to sort the other issues out first, no point wasting time fitting it up right if the lathe still cuts a taper without even being on the gap.

Couple of years ago I took a leap of faith and removed my gap. After a bit of perswading with a soft mallet it went back faultlessly. The finish in the mating parts gave the impression it would never go back but they did.

Cheers. Simon

Originally Posted by simonl

Couple of years ago I took a leap of faith and removed my gap. After a bit of perswading with a soft mallet it went back faultlessly. The finish in the mating parts gave the impression it would never go back but they did.

Cheers. Simon

Ive found with mine the tapper pins are a little sloppy and seem to always 'sink' down to where i dont want them.

Yes that makes it difficult.... but not impossible.

Tap tap here and there with a soft mallet and tightening a bit at a time may get you there in the end.

Simon

yeah ill get to it, need to get the twist out of the bed first.

With shimming being a total pain in the ass Ive decided to make up some jack screw with some m12 8.8 rod, not sure how sucesfull its going to be with using the sheet metal stand but i was planing on making up some 80x80x5 plates to act as plate to try spread the load over the base. Just after some opinions on this? or should i make up a thicker plate that covers the whole base of the lathe feet?

Originally Posted by brendanh

With shimming being a total pain in the ass Ive decided to make up some jack screw with some m12 8.8 rod, not sure how sucesfull its going to be with using the sheet metal stand but i was planing on making up some 80x80x5 plates to act as plate to try spread the load over the base. Just after some opinions on this? or should i make up a thicker plate that covers the whole base of the lathe feet?

The reason that you have problems with shimming, is most likely that your cabinet is not rigid enough. Everything feels rubbery and you have no control over the shimming process. 80x80x5 plates are not likely to change anything about this. The most efficient way to render a too light cabinet torsionally more rigid, is to bolt it to the floor. If that is not an option, I would consider making or purchasing a stronger cabinet.

If that is not an option either, get a thick kitchen bench MDF plate to cover your cabinet, or even better two glued together. You can find suitable chunks from cabinet makers (like the cutout piece for a large kitchen sink). It takes considerable force to twist these, certainly enough to untwist your lathe bed. You will see that shimming is much easier (you have much more control over it) if you can start from a rigid plane.

It is bolted down and i have been able to get a little twist out of it. Could probably bolt it down in a few more section. At the moment its only got 4 bolts

I found shimming to painful(thought granted I haven't leveled many lathes). I guess if you had a surface grinder handy it might be less painful, though the end result maybe better if the floor was up to it(which I dont think mine is). Take my lathe as an example, the base is about 200mm wide at the tail stock end. With a 0.02mm/m level your going to be aiming for better than 0.01mm/m(I think I'm being pretty nice there lol), divide that by 5, so you need shims 0.002mm apart. The you need to get the shim in near as damn it exactly the same spot each time. All bad enough with 4 bolts, 6 bolts makes it worse.

Maybe I'm missing something.

My stands have thicker sections on the top where the mounting bolts are and steel steel welded inside as a beam, maybe they dont all come like that?

I use jack screws....Its certainly cheap enough to try. As a plus you can get fall on the coolant tray at the same time.....which I stuffed up and didnt do

Stuart

i was planing on the jack screws between the stand and lathe. not too worried about coolant at this stage, and at the rate its going im sure ill be making a new stand in the future so i could incorporate jack screws that can be bolted down to the slab on the stand as well. Im trying to exhaust every option before making a new stand.

yes shimming is just something i dont have the patients for.