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Adjusting dead center on Metal Lathe

Posted: Wed May 20, 2015 7:43 pm
by RDPowell
This is for you guys that are experience metal lathe operators. I adjusted my tail stock awhile back ago because it was extremely off.
Seem to be okay till recently or I just noticed, either way it's off by 1/32" and I can't seem to get it any closer then that with my knowledge.
Anyone one know of a simple way to adjust this, or anyway to adjust this simple or not. Your help will be greatly appreciated. :wink:

Re: Adjusting dead center on Metal Lathe

Posted: Wed May 20, 2015 9:11 pm
by wdteipen
Which direction is it off, horizontal or vertical? Horizontal is easy. There should be a bolt or screw on both sides of your tailstock body. Loosen one while tightening the other until you get it back on center. If it's vertical, the only fix is to shim unless something else in the setup is out of whack.

Re: Adjusting dead center on Metal Lathe

Posted: Wed May 20, 2015 9:26 pm
by RDPowell
wdteipen wrote:Which direction is it off, horizontal or vertical? Horizontal is easy. There should be a bolt or screw on both sides of your tailstock body. Loosen one while tightening the other until you get it back on center. If it's vertical, the only fix is to shim unless something else in the setup is out of whack.
Well, after just checking it was off horizontally and vertically. :banghead:
I adjusted the horizontal but it looks like I'll have to shim it to get it to move up a stinking 32nd, so I reckon I'll live with it.
My lathe was made in the 40's by Dunlap and hardly worth the effort to adjust a 32nd out of.
But, thank you Wayne for the help, much appreciated. :wink: When I get famous like you maybe then I'll buy a real lathe. :lol:

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 3:46 am
by caskwith
Horizontal alignment is the most important, vertical doesn't matter so much unless it is very bad. Reason being you cut on the horizontal plan so any misalignment causes a taper in the work piece.

To set it up easily you need a steel rule and 2 brand new dead centres.

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 8:27 am
by RDPowell
caskwith wrote:Horizontal alignment is the most important, vertical doesn't matter so much unless it is very bad. Reason being you cut on the horizontal plan so any misalignment causes a taper in the work piece.

To set it up easily you need a steel rule and 2 brand new dead centres.
Chris, I adjusted the Horizontal, it's the Vertical now and we aint gona worry about it but, thank you sir.

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 8:42 am
by wdteipen
Actually, being off horizontal and/or vertical will result in oversized drilling but Chris is right that vertical doesn't matter for other functions of the lathe. The only thing it will mess up is your mortise size but if you're cutting integral tenons it's not really a big deal. If you're using Delrin it creates a pretty frustrating situation.

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 8:59 am
by RDPowell
Strange, cause it hasn't seem to give me a problem drilling an oversize hole at all and I use Delrin. The only thing I've noticed is the when I turn a shank on a stummel and then turn a stem they never seem to match. In other words one is off set from the other. This I thought was due to the center drill of the mortise in both stem and shank. Am I wrong and may this be cause by maybe a chuck's jaw being out of wack?

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 9:24 am
by caskwith
wdteipen wrote:Actually, being off horizontal and/or vertical will result in oversized drilling but Chris is right that vertical doesn't matter for other functions of the lathe. The only thing it will mess up is your mortise size but if you're cutting integral tenons it's not really a big deal. If you're using Delrin it creates a pretty frustrating situation.
Drills usually self centre to some degree. Best way to ensure proper sized drilled is to drill undersize and then ream to final size. Even if your tailstock is off a little you should still get good results this way.

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 9:26 am
by caskwith
RDPowell wrote:Strange, cause it hasn't seem to give me a problem drilling an oversize hole at all and I use Delrin. The only thing I've noticed is the when I turn a shank on a stummel and then turn a stem they never seem to match. In other words one is off set from the other. This I thought was due to the center drill of the mortise in both stem and shank. Am I wrong and may this be cause by maybe a chuck's jaw being out of wack?

If you drill and turn at the same time then things should be concentric. Are you removing the work at any point?

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 10:15 am
by RDPowell
caskwith wrote:
RDPowell wrote:Strange, cause it hasn't seem to give me a problem drilling an oversize hole at all and I use Delrin. The only thing I've noticed is the when I turn a shank on a stummel and then turn a stem they never seem to match. In other words one is off set from the other. This I thought was due to the center drill of the mortise in both stem and shank. Am I wrong and may this be cause by maybe a chuck's jaw being out of wack?

If you drill and turn at the same time then things should be concentric. Are you removing the work at any point?
No sir, Not till all work on stummel is done then I chuck up a rod to turn, drill, and mortise for tenon. But, I have just left the stummel on the chuck and removed the chuck and all and used a different 3 jaw self centering chuck for rod stock. And then when finished replaced the chuck with the stummel back on the lathe and turned the stem while inserted in the shank to do minor adjustments in size to match shank using a live center of course and they still came out different :banghead: .

Re: Adjusting dead center on Metal Lathe

Posted: Thu May 21, 2015 12:18 pm
by RDPowell
I just checked my dead center again, thinking maybe my chuck jaws were off a hair. (Tried do it the lazy man's way in the beginning)
Well, I reckon they were cause it centered perfectly to the head stock spindle and the Morse tapper in the tail stock.
So while it was off a 32nd horizontally it wasn't vertically. Turned a piece of steel rod stock pretty darn good. (I need new gibs on my compound)
We'll have to see what happens on my next stummel. I'm going to order some new jaws from Smokindawg the 1st of the month so I should see great improvement.
I think one jaw on my Oneway Talon chuck got tweaked a bit at some point after examining them closing.