Broken drill press - fixable?
 

Is this fixable? The chuck came right off the spindle tonight.

http://rennlight.com/gallery/image/5000287a.JPG
http://rennlight.com/gallery/image/5000287.JPG

Thom,

How was it affixed before? Usually a bolt or screw on arrangement.

If you look inside the chuck or the arbor what is there attaching the two? Hope its more than just a press fit?

Joe

What brand? That looks like a morse taper jam spindle. My dad has an ancient Delta that is held in place by friction only. All I have to do to get the chuck off of my dad's is hit the top of the chuck... It falls right off. It too, has actually fallen off on me while drilling. Take the bit out, shove it back on the spindle and give a few light taps from a mallet from the bottom.

Dave

The exact same thing happened to me this past weekend!

Block of wood and a hand sledge did the trick. Harbor Freight has another cheapie one on sale for $39. They are practically disposable. Heck, it's hard to buy a 1/2" chuck for $39....

The Jacobs chuck Thom has is great. I would not replace it.

Dave

So it's just jammed on there, eh? Ok, I'll clean it up and try to mash it back on.

Thanks!

would it help to knurl the taper?

No! Clean it up and leave it be. I even spray some silicon grease on the taper, so the parts don't sieze.

Dave

Thom,
That sort of thing happens all the time, even on the $10K milling machine I was using yesterday. As others have said, clean up the tapers. A good way to clean the taper on the press itself would be to turn on the motor and hit it with a scotchbrite pad. You want it as smooth as possible. Clean the inside taper of the chuck too. The taper relies on clean metal to metal contact to work. Then install the chuck. I usually give it a few taps with a dead blow hammer, just to be sure.

As to why it happened, well that's another topic. Lets just say a drill tries to draw itself into the metal it's cutting. I'd recommend a bit more downward pressure when drilling, to keep the chuck fully engaged with the spindle taper. If the pressure is too light, you'll have the problem you experienced tonight.

Jim

slodave is right. Knurling the taper would render it useless. I believe that there is some sort of molecular interaction that goes on with a taper fit. Smooth tapers=tight fit. (that sure didn't sound right, did it? :eek: )

I also agree with Jim, clean the taper and the chuck. The taper seems to be in good shape. I said I use silicon grease earlier.... Actually I use a little lithium grease on the spindle and gentle wipe it off. You don't want any rust to develop between the the two parts. Thom, I think you live somewhat near the ocean??

Dave

maybe im just not understanding how the chuck actually is held on...

Yep, I retract my statement, knurling would be a bad idea. Didnt realize how it was secured..

On my new Delta press the instuctions stated that a degreaser dhould be used to clean both the spindle and chuck. I used brake cleaner, and I have taken it off to inspect for rust (I'm a bit anal about things like this) and it looked perfect.
-Jeremy

Yep, just clean it up real good with scotch brite and ram her home.

It's called a "self locking taper". There are several types and sizes of them. A old tool maker trick to make the fit lock up even tighter is to use a dusting of chalk.

A follow up on Jims idea of the drill pulling off. In soft metals where the drill trys to pull in it is a good idea to grind a 0 or slight negative rake at the tip. Then the drill press drives the bit into the material.

I was using a 3 3/4" hole saw on 12ga steel, and this press doesn't have the torque needed when the hole saw gets a good bite - it would stall - so I was working it down very slowly.

Last night I cleaned everything up with a scotchbrite pad, ran the 'claws' of the chuck up inside so I wouldn't mangle them, then pounded it on with a hammer and it's working fine now - thanks!