lathe help

[pipeguy]

my lathe apears to to be wobleing (not spining true) my drilling is off center. could this be that the shaft is bent??? I can see it woble when my lathe jaws are on your help would be appreciated thanx Bob Clark

[KurtHuhn]

It would take a serious amount of torque, and a pants-changing event, to bend the spindle of most modern-ish lathes. If this didn't happen, the likely problem is that the chuck is screwed. What kind of lathe is it? If you put a Jacobs chuck (drilling chuck) in the headstock spindle, does it spin true?

[pipeguy]

It's an old power king lathe. jacobs chuck is on the tail stock its the 4 jaw that appears to woble but i"ll put the jacobs on the head stock to see.

[pierredekat]

Is your lathe something like this one?

my lathe apears to to be wobleing (not spining true)

So it's not the whole machine wobbling, just the chuck wobbling, right? If that's the case, as Kurt says, your chuck is likely screwed up.

Does your chuck have a back plate? If so, it could be that the chuck and back plate aren't mated properly.

And you may be able to remedy that by loosening the screws and sliding things a bit. But you may have to get a little more sophisticated and re-drill and remount the chuck on the backplate.

my drilling is off center.

If your lathe is like the one in the picture above, do you see those two screws that enter the base of the tailstock, one from the side facing you and one entering from the side opposite you?

Those are for centering the tailstock on the axis of the headstock. What you'll want to do is loosen one and tighten the other until the headstock and tailstock are aligned.

You may also have to do some shimming, if the headstock and tailstock are misaligned from top to bottom, but start with the side to side adjustment and see what that gets you.

Also, when lining up your drilling on an independent 4-jaw chuck, you want to line things up, then rotate the chuck 180 degrees and see if things are still aligned.

If not, you will need to loosen one side of the chuck and tighten the other until the block is centered on the axis of the headstock.

[pipeguy]

The lathe is wobleing from the headstock. When I attached the the drill chuck and the morse taper in the head stock shaft the drill bit was clearly wobleining then I removed the jacobs chuck and just left the taper in the headstock and the wobling still continued the lathe is belt driven by a motor thats on a hinge to keep tension the motor bounces a little. could this be from a bad shaft your thoughts would be appreciated thanx Bob Clark

[KurtHuhn]

You know, that does sound suspiciously like a bent spindle - especially since you mention the motor bouncing around on its mount. However, it might just be the bearings are worn, allowing the spindle to shift in the races and move around. The only way to know for sure is to remove the spindle from the headstock and inspect it on its own.