# Tail Stock Alignment



## Swerdk (Oct 6, 2015)

On my PM 1236 I am using a test bar three-quarter inch diameter/ 12 inch long between centers to test my alignment. I mic'd my bar on both ends and it is exactly 3/4 Without skimming it. What is the reason for skimming off the end of the bar if it's exact before I ever start? I am thinking I'm just running the dial indicator along the bar and as long as the bar is exactly 3/4 all is good. Am I missing something or do I have to realign my tailstock by first skimming the ends.
	

		
			
		

		
	




Another question is if I only have a test indicator to test if the tailstock is aligned , will that give me accurate readings? I know all the videos show a dial indicator so just want to ask. My dial indicator set up is not completed yet


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## Andre (Oct 6, 2015)

On a new lathe, that has been leveled and properly setup then you can most likely get away with just using an indicator.


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## Chuck Torman (Oct 6, 2015)

As long as your test bar centers are drilled TRUE on center and your test indicator shows everything to be round and consistent from end to end, you should be good to go, I personally see no reason to skim cut the end(s). Make sure that your bed ways are level from end to end, if they are not, you will be off every time that you change the length of your work piece. Good luck.


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## MozamPete (Oct 7, 2015)

I think part of the reason is although the bar may be the exact diameter (say a new length of drill rod), it is hard to ensure the centre drill holes are dead centre to the bar without putting it between centres and skimming the bar (or indicating each end of the bar in a four jaw chuck and actually cutting the 60 deg centre, not drilling it, to ensure it is on centre).


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## chips&more (Oct 7, 2015)

Howdy neighbor, not sure on your intent? Using a test indicator is just fine. Be aware, when you have a sleeve, two dead centers and test bar from? That your uncertainties can add up. Nothing is perfect.  It’s nice to try and get to perfect though. Chances are that if you took away all of your set-up and then reset it up you would get a different number. All because of the uncertainties/tolerances/wear in the tooling and your machine. If it was me at my age, I would just use the machine before I fall over…Good Luck, Dave.


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## Fabrickator (Oct 8, 2015)

I use about the same size and length aluminum bar for just this reason.  I made it myself in my lathe so I know that it's accurate.  I chuck it up on centers and run a .002 cut the length of the bar and use a vernier mic to ensure that it's dialed in end to end.


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## RJSakowski (Oct 8, 2015)

Rollie's Dad's Method can be used for tailstock alignment as well.  The test bar would be mounted in the headstock, either with a center and lathe dog or by lightly gripping in the chuck.  The opposite end of the bar would be center drilled and engage the tailstock center.  Measurements would be made close to the headstock center/chuck and the tailstock center.  As long as the bar is round, an accurate measurement of tailstock offset is possible.   In this case, a smaller diameter bar is preferable as there is less likelihood of flexing of the bar transmitting stress to the tailstock center.

Bob


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