difficulty setting up a lathe for the first time

Hello,

I am attempting to setup my newly acquired, but older than I, Logan bench lathe 210. I used to own a little C3 mini lathe years ago and finally found something with a bit of power. I have been watching MANY YouTube videos and reading a lot but still having some difficulties setting up the bench lathe.

I have the wood table leveled with a carpenter level (the lathe did not come with the iron leg option sadly). I am using shims and a self calibrated machinist level on accurate 123 blocks. The headstock and tailstock almost perfect level front to back. I have not spent as much time chasing headstock to tailstock leveling but it is close (I understand this is not as critical). I have waited for the bubble to settle during readings though I have little control over the weather.

Every time I place my center drilled .5in diameter 11in long aluminum bar between centers (dead on headstock and live on tail) and make a cut I am off (currently .005 larger at tail). I have tried adjusting the tailstock but that never seems to close the gap just switch which side gets the error.

Given my attention to balancing the ways I do not expect any taper is due to twist. I have used dial test indicators, from the compound, on the headstock spindle and it runs true in 2 axis so I do not suspect it's alignment from this test. Testing the tailstock has been more complicated likely because I do not fully understand how to do so with the tools I possess. It is also possible the ways are worn due to use and age though the old timer I purchased it from seemed to be quite capable so it's not my first suspect.

In short, I am trying to get my first big boys lathe setup to run true before I start. I am hoping you all can help me figure out what I am missing.

Thank you.

If I understand correctly, you are using a live center in the tailstock. Before you start chasing twist in the bed, look at adjusting the tailstock. It may be that your previous LSO (lathe-shaped-object) did not have any adjustment in the tailstock, but it is a standard feature on any real lathe; this adjustment allows you to cut tapers on purpose when turning between centers. But of course, it also allows you to adjust the tailstock to eliminate a taper.

You need to use a dial indicator when you adjust the tailstock. Generally you will make small adjustments like this mostly by tightening the appropriate screw; if you need to loosen the opposing screw, you will get a relatively huge movement.

awake said:

You need to use a dial indicator when you adjust the tailstock. Generally you will make small adjustments like this mostly by tightening the appropriate screw; if you need to loosen the opposing screw, you will get a relatively huge movement.

Click to expand...

+1 to this. Usually if I need to loosen anything when making fine adjustments, I re-tighten it right away before going to the other side and adjusting from there. You'll get the feel for how much to do so pretty quickly.

Are you adjusting the tailstock half or the full error you're reading?

You should be adjusting it half.

Also if you're not, save yourself a lot of time and just cut a test collar at both ends. Your test bar is far too spindly for any meaningful data in the middle of its length.

Just did the same thing on a Colcester and I discovered the live center I was using seemed to have some play,changed to a different center and was able to get less than.0002 over 10" . BUT I am using 1.5 OD material,your 1/2 is a way too limber.

I would start with something lie a 2" test bar of 7075 Aluminum. Chuck it well but do not use the tail stock. Undercut the center a few thou. then take a skim cut at both ends. You will have to get it to cut the same size on both ends otherwise it will never cut right with the tail stock. If your ways are worn to where the tool does not remain at the same height along the cut the size will change. You should be able to get it to cut depending how bad it's worn by moving the tail stock. Don't try to calculate it, put an indicator on the tail stock and move it .001 in the direction needed. Take a test cut again. Don't move the tails stock, simply adjust another .001 until you get both ends of the shaft the same size.