I have a question about lathe alignment

[Mark_f]

Mark, it seems nobody is willing to comment on your question about headstock misalignment. I've been chasing a similar problem with taper on my old 12" Utilathe, and found some relief by adjusting torque on the four headstock bolts. Also discovered the headstock has been shimmed at some point in the past. Further, doing reasearch on this on a rebuilders forum, I discovered some comments that suggest that headstock bolt torque does indeed affect taper. Which makes sense if you consider drawing the right front edge of the spindle down and away from the lathes true centerline will certainly create a taper in long work.

Can't hurt to experiment with removing the headstock and looking for debris bits underneath, then remounting. Or alternatively, just loosen the appropriate bolts and take a series of cuts to see if you can improve the situation.

Glenn

Glenn,
Thank you. It may be possible that I threw it off tightening the headstock clamp bolts. At least I have a plan now.

 

[rgray]

Before I do all this, I was thinking about putting a 3MT test bar in the spindle and using an indicator

I like the "rollies dad method" (google that) for figuring out bed twist. Worked well for me. Requires no precision test bar.
It amazed me how small of an adjustment it took to show an easily measured difference.

 

[kvt]

Mark, I was thinking of the floor, Not as a platform but also not knowing what you have your lathe on if it has feet etc, and are placing the weight of the cabinet, lathe, and everything on just those areas. An the areas were not direct on top of the floor joist. Then the OSB can start to give, and I have seen things start to sink into it and punch through. For some reason I do not trust the stuff any more. I would double up the OSB under it, put a piece of good Plywood, or even what one said I about taking and placing 2x4s and putting under it. Then start working on putting a good platform together to mount the lathe. I like the door idea then put your current piece of steel over that for the platform to mount the lathe.

Also the torque on the head bolts, I have actually watch this one on one of my lathes. Was working on the alignment when still had the bar in, then went to torque the head bolts down. As I torqued them down I could watch the gauge move around. My real surprise was how much it moved. But mine did not use a way to keep it in line either. But I remember 4gsr said something about not fully tightening the bolts down on the head for a South bend He had.

 

[Technical Ted]

Mark, you've gotten a lot of good information here and maybe even a little bit of information overload! Plenty of things to test/try when you're feeling better. The only thing I would like to mention at this point, is if you do decide to buy a test bar, if you buy one with a 3MT everything has to be in perfect shape for it to function as designed. Meaning, your spindle taper, both the internal and external tapers on your spindle adapter and the taper on the test bar have to be in perfect shape, no dings, dents, errors at all or the far end of your test bar has very little chance of running true and will wobble. There are test bars that you can buy/use/make that either go between centers or you can put in a four jaw chuck (or extremely accurate 3-jaw chucks), or even a collet so you can tap the far end to get it to run concentric with your spindle. If using a chuck, clamp up on the very end of the bar using something soft, like aluminum or copper, under your chuck jaws so you can indicate the far end in.

Just a little more food for thought!
Ted

 

[Silverbullet]

Permalam beams would anchor the floor and base , those babies are about 3x 12 , manufactured lumber , strong buggers. They should stiffen it up plenty. .
Mark sorry your down bud , ill send some extras to heaven. On your behalf.

 

[Splat]

Get rid of the wood. Wood absorbs moisture and will kill any leveling you may have obtained at that time, not to mention its expanding and contracting nature. You need a good foundation., preferably concrete IMO. It ain't gotta be deep either. 3" would be minimum for me. Without the solid foundation you'll be chasing level each time you use the lathe. Good luck and feel better, Mark

 

[MikeWi]

Get rid of the wood. Wood absorbs moisture and will kill any leveling you may have obtained at that time, not to mention its expanding and contracting nature. You need a good foundation., preferably concrete IMO. It ain't gotta be deep either. 3" would be minimum for me. Without the solid foundation you'll be chasing level each time you use the lathe. Good luck and feel better, Mark

+1, but instead of replacing or augmenting the floor, treat the building as a ship. Remember you said that the ship is never level and moves around all the time, but the lathe is still aligned to itself right? So build a sturdy frame to go under the lathe. As long as it doesn't flex, the lathe can be aligned, and will stay there (reasonably speaking) regardless of what the floor does.

 

[T Bredehoft]

Everyone is talking about leveling the lathe. While a perfectly leveled lathe is awesome, the same result can be achieved with both front and rear pieces of the bed being parallel. Remove the tail stock, put the saddle half way between head and end. Rig a height gage on the front with the indicator on the back, set zero on one end, and put it on the other end. make both ends the same and your lathe should cut straight.

 

[eeler1]

Agree with Al earlier, you walk around from the front of the machine to the back and I'll bet it goes out of level (or twist).

Big shops here in the north west often used to have wood floors, but were stable and impregnated with oil. Some had the wood stood on end, maybe 4x6's or larger. No flex at all, and actually durable where the machines were placed.

If you pull the headstock, it's a good opportunity to see about level using that part of the bed that has no wear. But then when you walk over to put the level away it will flex back out.

Maybe put it on springs?

 

[Tozguy]

Well ..... if it comes to rebuilding the shop, I'm afraid I will have to live with it.

Thank you all for all the good information. Rebuilding / re-enforcing the floor is not an option as I would have to tear down the building to do it. But I like the idea of setting a thick wooden base under the lathe and leveling to that.