Shars 12" Precision Level

[Technical Ted]

Don't use your tail stock. Just chuck up a piece in your chuck. The tail stock would control the taper not the potential twist in your ways and therefore should not be used. Regardless of the way you try to align your tail stock prior to this test I would never trust it. See attached below from South Bend.

Ted

 

[Janderso]

OK, that's why they say to use a large od piece, to reduce deflection. I don't have an mt4 bar. I could use a dial indicator and run it down the side at 9:00 to check for the same thing right?
I see what you are saying about between centers. I understand that's the best way to get accurate (no chuck runout) cuts.
I'll try it.
Thanks Ted

 

[Bob Korves]

OK, that's why they say to use a large od piece, to reduce deflection. I don't have an mt4 bar. I could use a dial indicator and run it down the side at 9:00 to check for the same thing right?
I see what you are saying about between centers. I understand that's the best way to get accurate (no chuck runout) cuts.
I'll try it.
Thanks Ted

Machine the bar in place so it is concentric and in line with the spindle center line axis. That way any taper will show bed twist and/or headstock misalignment and/or worn bed ways. Look up "Rollie's dad method."

 

[Janderso]

I just printed out the PDF.
Very simple and it makes sense.
I have a piece of drill rod. 12" long X 3/4.
Thanks

 

[benmychree]

Put the drill rod away; just chuck up a piece of steel long enough for the test and perhaps an inch in diameter, relieve the bar projecting from the chuck so that you have a 1/4" long portion near the chuck jaws and at the end of the bar toward the tailstock; take very light cuts on both raised portions at the ends and adjust leveling until both are the same size, or as close as possible; all we are worried about is that the lathe cuts reasonably straight. Wear on the ways near the headstock may render complete absence of taper impossible, the thing is to reduce taper as much as possible; "perfect enough".