Lathe levelling

[Janger]

I need to level my lathe. John C tells me I need proper feet. Thought I would discuss it here instead of just with @Dabbler.

I found a good thread on it: http://www.practicalmachinist.com/vb/general/lathe-leveling-mounts-177458/

Some people say buy some from Enco, another poster has a home made solution with big bolts and carriage nuts. Other threads suggest a hockey pock and bolt solution but these guys think that's a poor idea. So what kind of feet is one problem. The other problem is the level. South bend lathe guide from 30-40 years ago says a 12" precision level must be used as any other kind is not accurate enough. I don't have one and they are expensive. I do have one of these digital ones. Calibrating it is a problem.

 

[Dabbler]

Getting it to level with the digital ones is a great start. You will need to put a parallel across the ways to check in that direction. After that, an 8" precision level is fine.

Do you have tapped holes in your base? If so, then just start with bolts. You can later add feet pads under them. Besides you will probably need to redo the level on the lathe after a few months anyway as things settle out.

Dale at 'metal tips and tricks' on youtube has a very good description on why and how to level your lathe. He uses a plumb bob, which is a lot cheaper than a precision level...

try youtube dot com / watch?v=2qIdsnl5vpg

or try Tom Lipton at oxtoolco at youtube dot com / watch?v=zIDL77qt1tI

 

[PeterT]

Agree with Dabbler. I just went through this rigamarole on my lathe cutting a slight taper. I chased down the levelling avenue, only to discover my headstock adjustment was slightly out. This is exactly what is shown on Tom Lipton (Oxtool) Leveling and Setup of the metalworking lathe P1 & P2. Another is Keith Fenner Let's Look Under The Old Girls Apron Part Eleven. This Old Tony has a similar demo but he only talks about the hows & whys of lathe levelling.

To my mind the proper sequence goes:
- lathe level as accurate as you can get it in both fore-aft & cross-bed axis
- adjust headstock angle (assuming it is adjustable). Use the test bar cut method or DTI-ing off a precision test bar held in headstock spindle socket (ideally not introducing a chuck into this)
- then (and only then) with headstock true, introduce tailstock concentricity alignment into the mix because it references off headstock rotation

I've seen a lot videos & articles where people start jacking the lathe feet right off the bat to correct taper. This is called lathe levelling, but what they really mean is 'lathe bed twisting' to dial out a taper cut. I can only assume this is the recommended go-to method if your headstock is fixed (unable to adjust in top view plane). Worded another way, if your headstock is out & you haven't dealt with it & then you twist your lathe by jacking the feet up or down to compensate, you now have 2 problems that are somewhat masking one another.

My garage floor has a mean slope & my feet are extended on one side as far as possible. So my headstock is slightly downhill but very level laterally across the ways. I was concerned about this but my machinist buddy says its the cross level that is important. So far that has held true, its cutting very accurate now that I tweaked the headstock. That was the issue.

 

[aninchlow]

I've done the exact same thing with a few variations.
(1) leveled the ways both directions and bolted the lathe to the concrete
(2) put a peice of ground 1" stock through the head and had the excess 2' sticking out over the bed. Using the spider and the 4 jaw I centered the bar with runout gauges and got it as close to perfect as I could.
(3) ran the cariage down the bedway with a run out gauge and adjusted the headstock until runout was minimal, now I know the head is true to the bed.
(4) ground 1" stock between centers and measured for wobble on both ends. Adjusted the tailstock until it was gone. I now had a reasonably straight lathe.

 

[Tom O]

I need to level my lathe. John C tells me I need proper feet. Thought I would discuss it here instead of just with @Dabbler.

I found a good thread on it: http://www.practicalmachinist.com/vb/general/lathe-leveling-mounts-177458/

Some people say buy some from Enco, another poster has a home made solution with big bolts and carriage nuts. Other threads suggest a hokey pock and bolt solution but these guys think that's a poor idea. So what kind of feet is one problem. The other problem is the level. South bend lathe guide from 30-40 years ago says a 12" precision level must be used as any other kind is not accurate enough. I don't have one and they are expensive. I do have one of these digital ones. Calibrating it is a problem.

This is a old thread but if anyone needs one I just picked up this 12 inch Moore &Wright for $80.00 .

 

[Dabbler]

what a deal!!

 

[4Jawbilly]

Leveling a Lathe is not absolutely necesary.

Most Oceangoing Freighters have a Lathe in there Engine Room, bit of an art to work on the Lathe when a part is needet and the Weather is rough.

Cheers

 

[Johnwa]

Twisting, or untwisting, the bed is the standard alignment method for the 9” southbend. There are a couple of screws built into the tail stock foot expressly for that purpose. Ideally there will be no twist, but a little twist can take care of a slight spindle misalignment.

4jaw is right that a lathe doesn’t have to be level, but leveling is the easiest “measurable” to ensure the bed isn’t twisted. It doesn’t need to level as long as both ends of the bed are out of level by the same amount.
Google “Rollie’s Dad’s method” for an alignment method that doesn’t require a perfectly straight and centered test bar.

The ultimate test tho, is whether or not the lathe cuts a taper.