Lathe alignment help...

[salindroth]

Thanks. I have a bench lathe and haven’t installed foot adjusters. That would be a good addition.

There is a truly bogus aspect to my set up. The lathe straddles two different benches - a much-used Craig’s List purchase and a smaller home-made bench. Obviously this compounds the challenges with leveling, let alone aligning. It’s crazy that the lathe is as well aligned as it is.

In fact I had previously gone down the shimming rabbit hole. I got the ways level with respect to gravity but the alignment of ways to spindle was miserable (3 thou off over 6”!). Weirdly, additional shimming to correct this made it so the lathe would not sit solidly on the bench(es). I could rock the lathe forward and back! This is probably a consequence of the stupid workbench arrangement. I removed the shims (giving up on alignment with gravity) and the situation improved dramatically. Modest shimming on one foot got the alignment of ways to spindle within 0.0005” over 6”.

The other issue is that I think the ways are worn 0-7” from the chuck, where most of the use has occurred. I infer this from aligning the tailstock with the spindle using a lathe alignment test bar, which allows me to check alignment over a much greater distance.

I can get the tailstock perfectly aligned with the spindle 0-7” from the chuck, but beyond this the cross slide abruptly shifts 1 thou closer to the workpiece over the next 1” of travel farther from the chuck. By the time the cross slide is 11” from the chuck it’s off by 2 thou. The abruptness of that first change suggests wear rather than twist. Curious to hear your opinion.

But you’re right, I can chase that last 1/2 thou in the first 6 inches for ways-spindle alignment. I need to resolve the workbench issue first.

Scott


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[mikey]

I have to admit that your scenario is challenging. If you're getting a half thou as it is, I would leave it alone. No point chasing tenths when you have that much wear on the ways near the chuck. I would use it as is and maybe someday, if you buy a lathe that is in better shape, it might be worth setting it up well. I do think that having adjusters under the feet of the lathe and also the cabinet are worth having.