Another lathe leveling question

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Clunker1

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I have a used enco 13×40 lathe. As is common with asian lathes, the head stock is adjustable. When I first moved the lathe into my shop, I leveled it with a make shift plumb bob level and it cut pretty good for a newbie. Then one day, I crashed the carriage into the headstock and it began cutting tapers.

I did a lot of reading about leveling a lathe and found almost all discussions related to leveling lathes with fixed head stocks. My concern was that I believed I shifted the head stock alignment when it crashed since its unlikely that the leveling was impacted.

I read a post that suggested to face a large diameter disc and check the face with a test indicator to check head stock alignment. As the test indicator moves across the face on the back side of center, it will show misalignment. I aligned the headstock with this method with the largest diameter I had, about 4 inch, and the lathe cut pretty good again.

Now my projects and skill require more and more accuracy. I want to properly level the lathe and check alignment of the headstock more accurately. I plan on facing a much larger diameter disc to check head stock alignment, but was wondering if I should invest in a machinist level to start the process on the right foot. The Starrett 98-12 is accurate to .005 in 12 inches. Is this the way to go or is a different level required? Is a 98-8 or 6 acceptable as the are not as pricey? Should I level first, adjust headstock next, and then cut test bar for taper indication?

Thanks for any input here.
 
Leveling the lathe is not as important as getting rid of twist, sag, and ensuring it is all in plane with itself.

The term "levelling" is intended to refer to the lathe being level to itself.

Have a quick look at this video by Joe Pie

 
#98 Starrett levels are all the same accuracy per foot regardless of length, and I think they are not accurate enough for lathe leveling, the #198 with .0005" per foot is the standard for lathe leveling for removing TWIST from the bed, absolute leveling is not where it's at, removing twist IS.
 
Again, joe pie is talking about an integral head stock lathe. Things get more complicated when you have head stock alignment to deal with as well as twist. If you go chasing what you think is twist and the issue is also headstock alignment, you can be chasing your tail.

If absolute leveling is not where its at, why use a more accurate level.

I was hoping someone had experience dealing with sag, twist, AND head stock alignment.
 
I had to deal with the headstock on my SC3 7x and I also have that job coming up on the 7x I am rebuilding. It is a pain, but do-able.

As for Joe pie, the principles are the same, to a point. The only thing he does not really reference is squaring the headstock to the bedway and the way to do that is the disc test as you have already done. there are other methods, but those are far more involved.
 
Clunker1 said:
Again, joe pie is talking about an integral head stock lathe. Things get more complicated when you have head stock alignment to deal with as well as twist. If you go chasing what you think is twist and the issue is also headstock alignment, you can be chasing your tail.

If absolute leveling is not where its at, why use a more accurate level.

I was hoping someone had experience dealing with sag, twist, AND head stock alignment.
Click to expand...
When I say absolute leveling, I mean that the bed needs to be without twist, but not level to an ideal plane such as a perpendicular to a radial line to the center of the earth, if there is such a thing. The leveling of the ends of the tops of the ways at each end of the bed is the way to remove twist, this is essentially what Joe was getting at, but leveling (or bringing the axis of the spindle into parallelism with the axis of the ways) enters into the ability to make straight cuts.
 
I also have an older Enco 12 x 36. I have been curious about headstock alignment as well.
 
I'm definitely NOT an expert, simply asking the question: If it wasn't cutting a taper before the crash, and assuming the tailstock was not in use when it crashed, why not buy a morse taper test bar that fits the headstock and indicate it in straight?

I guess having the bed level first makes sense as a general principal too. But if the headstock is off a level on the bed won't tell you that.
 
@Clunker1 If you are taught by a professional machine rebuilder, the headstock is always aligned/checked first. Nothing happens until this critical step is accomplished. This step is often skipped by youtube 'gurus'.

This can be done before trying to take the twist out of the lathe bed. Because you can get close with machinist levels, there is no harm in getting the lathe bed close with the levels. You indicate in the headstock. I shoot for .0002 in 4" for my light lathes.

THEN take the twist out of the lathe bed, then align the tailstock.

You can then go back and recheck the headstock, bed for taper, and tailstock to get closer if you are OCD.
 
Bed leveling is irrelevant. Lathes on ships are never level.

Bed twist is what you are after. Get the twist out, or make sure there is none to begin with. Once that is done, then concentrate on squaring the head up. Again, get the twist out and then deal with the head alignment. Like you said in post #4, you will be chasing your tail if you are trying to solve more than one variable at a time.
 
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