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Tail stock alignment with out center adapter

Awleaphart

Aluminum
Joined
Mar 16, 2019
I Purchesed a used lathe that’s missing the adapter that holds the #4 Morse taper in the head stock. To align the tail stock with the head, I put a 4 Morse taper in a 4 jaw independent chuck and zeroed with a test indicator. I installed an Edge tail stock alignment bar between centers and when indicated on the Edge bar at chuck end I get .003 runout. So I changed up and zeroed my test Indicator on the edge bar at the chuck end. My question-is this the correct way to do this ( zeroing The chuck on the Edge bar instead of the 4 taper it’s self? Or is there a better way of doing this?
Thanks A Leaphart
 
Im trying to picture what youre doing. Youve an MT4 socket in a 4jaw, with a dead centre in that socket, then indicating an 'Edge alignment bar' between centres? If so youd probably be better off turning a centre in the chuck and using that instead.

Id suggest you go a different way though.

Aligning your tailstock:-
i) Before you do anything else, level your machine as best you can.
ii) Check and align your tailstock to the spindle, you can indicate this vertically also.
iii) Back out the TS and turn a couple of collars, preferably between centres. You can mic the collars and indicate them as you would your edge bar. In the real world you might see some difference here in what you cut and indicate, due to deflection/wear yada yada.

Happy lathing
 
If you chuck a part in a 3 jaw, 4 jaw or collet and then turn the OD of that part you get the true position of the headstock, you can turn a center to a 60* point and get dead center of your head stock off a center. Yes 60* the angle can even be off a little and you still have dead center. You can check the turned angle with a fish gauge and get near perfect.

Yes the turned part held in the headstock should come out/measure straight even if the chuck held end is off/wobbling..if your head stock is straight to the bed..agree level makes the bed straighter.

Wore out bedways makes things difficult.. then you have to consider the part not just the lathe.. different length parts will/may change how straight the part will be if chuck held or between centers..

Yes to be good/right your head and tail should be straight to your bed, and the bed good..

For just the place close to your chuck you can turn a point and then bring the tail center close and eye ball to about .002"..but down the bed it may be off... and the head and tail may not be straight.
 
For a quick test, mount a dial test indicator in your chuck and sweep the interior of the tailstock taper. Even if the indicator is off center in the chuck, it will always be sweeping from the same arc and it will show any misalignment of the tailstock/headstock system. Just like sweeping a part on a manual mill for centering.
 
For a quick test, mount a dial test indicator in your chuck and sweep the interior of the tailstock taper. Even if the indicator is off center in the chuck, it will always be sweeping from the same arc and it will show any misalignment of the tailstock/headstock system. Just like sweeping a part on a manual mill for centering.

Vertical axis machines are easy to sweep. Sweep with an indicator with a horizontal axis and you usually get junk results. The sag of the indicator will be significant. If you doubt this, set up your indicator on a robust plate. Now turn the plate upside down and read the indicator to see how much sag you have.

For best, easy results in aligning a tailstock, chuck a suitable piece of stock and turn a plug the same diameter as your tailstock. Now you can mount an indicator on your carriage and compare the readings from the headstock to the tailstock, where indicator sag will be identical in both axis. Also, run the tailstock spindle out and check the alignment of the tailstock itself.
 
For best, easy results in aligning a tailstock, chuck a suitable piece of stock and turn a plug the same diameter as your tailstock. Now you can mount an indicator on your carriage and compare the readings from the headstock to the tailstock, where indicator sag will be identical in both axis. Also, run the tailstock spindle out and check the alignment of the tailstock itself.

^^^ That's my preferred method too.
 








 
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