Leveling the lathe for twist

Further, what I have done that helps speed up the process is take a light cut and then use a tenths DTI to tweak things in before taking another light cut to verify by going back and forth between the two surfaces with the DTI and adjusting accordingly.

I'll also do this if I'm actually machining on a work piece and I find I'm getting a taper and want to tweak it out prior to my finish pass. So, I'll have one longer machined surface rather than two small ones and just check the entire length with the DTI and tweak it in.

Ted
 
Thanks for the response.
I took great care in setting up my lathe using the two collar test. As a newbie I was more adept at using a micrometer but was not so certain how much deflection was occurring so I took several 'spring' passes. I found it to be delicate work at the time and the lathe (a 12x36) not always responsive to the tweaking. Fortunately the lathe is sitting on a very stable cement slab in a controlled atmosphere far from tectonic faults so all I do now is keep an eye on the work in progress for any signs of twist in the ways.

PWF, how is it going?
 
If you don't own a precision ground test bar you put in the spindle taper, you can turn the 2 collars different diameters from a worn lathe. Just mike them until they mike the same size. Then you can twist and indicate the bar so it reads zero zero or plus a few tenths + on the tailstock end to compensate for push away. This way is faster then taking multiple cuts. Or if your moving the head if it is one a pin like the Asian ones and Colchester have. Another test you can make is to chuck up a 4 to 6 inch x 1 to 2" thick, round bar stock of aluminum and face it. Then indicate the face. It will read zero zero from the outside to the center where you just cut. But then continue cranking past the center and indicate the back side of the aluminum bar, this will show the error of the cross-slide doubled. How about one of you do that test and take some photos for us to see.
 
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Don’t forget to calibrate your level before you start..l...
 
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