MT's with a draw bar

[lsfoils]

Hi all,

Spent a fair amount of time this A.M. helping a friend who was trying to remove a morse taper arbor from a large drill press spindle. This drill press was equiped with a cross slide table and variable speed spindle (by way of variable pitch pulleys). Nice machine, but someone had really reefed on the draw bar to seat the taper.

My freind and a few others had spent considerable time beating either on the draw bar or the wedge. He needs new bearings now. And probably a new spindle.

We got it out by removing the quill from the machine and placing it on a 12 ton press. We inserted a new rod; the other was shaped like a straightened "s" near the threads, and pressed it out. Not without some grief, of course. Our first try was halted when the spindle and quill looked out of square after applying a fair amount of pressure. After righting it, we gamely went at it again to the maximum of the press. Nothing happened. Taping soundly on the press with a rubber mallet didn't help. So we relaxed the pressure, checked our set up and went at it again.

When it finally let go, it sounded just like a gun shot. This stirred a little excitement for a while. But the arbor was smooth as glass on the taper; no galling, just a really good taper lock.

My advice to anyone who has a draw bar on a Morse Taper spindle: slap or tap the arbor home like on any machine without a draw bar and just snug that bolt up a little bit with a wrench!

-Doug

[CNCnUtZ]

Originally posted by lsfoils Hi all, Spent a fair amount of time this A.M. helping a friend who was trying to remove a morse taper arbor from a large drill press spindle. This drill press was equiped with a cross slide table and variable speed spindle (by way of variable pitch pulleys). Nice machine, but someone had really reefed on the draw bar to seat the taper. My freind and a few others had spent considerable time beating either on the draw bar or the wedge. He needs new bearings now. And probably a new spindle. We got it out by removing the quill from the machine and placing it on a 12 ton press. We inserted a new rod; the other was shaped like a straightened "s" near the threads, and pressed it out. Not without some grief, of course. Our first try was halted when the spindle and quill looked out of square after applying a fair amount of pressure. After righting it, we gamely went at it again to the maximum of the press. Nothing happened. Taping soundly on the press with a rubber mallet didn't help. So we relaxed the pressure, checked our set up and went at it again. When it finally let go, it sounded just like a gun shot. This stirred a little excitement for a while. But the arbor was smooth as glass on the taper; no galling, just a really good taper lock. My advice to anyone who has a draw bar on a Morse Taper spindle: slap or tap the arbor home like on any machine without a draw bar and just snug that bolt up a little bit with a wrench! -Doug

Yeah. I thought the taper itself was the locking mechanism...and the drawbar is just for safety.
If you even need to do more than tap on the drawbar with a deadblow to remove it then IMO you are tightening it way too much to begin with...

not to mention killing your bearings in the process, as a pretty hard whack with a hammer is equivelent to much more load than ANY bearing is rated for.