Slipping mortise tenon

[Webb Willmott]

My old Delta drill press is acting up. The Jacob's chuck MT don't want to stay in. I'm sure somebody has run into the problem with MT's not wanting to stay in and looking for how to fix.

 

[robo hippy]

It may need to be cleaned out. I did have problems with mine not wanting to stay in a long time ago. It ended up being that the drill bit I was using was inserted too deep into the chuck, and that did not allow the morris taper to properly seat. Maybe a combination of things.

robo hippy

 

[Richard Coers]

You sure it’s a Morse taper?

 

[Gord Cameron]

- Clean the male and female parts with mineral spirits or a very light lubricant (e.g. WD-40 or Boeshield T-9), then wipe to remove as much solvent or lubricant as possible;
- Open the chuck all the way so the jaws are fully inside the nose of the chuck body and insert the morse taper in the drill press quill;
- Put a wooden block on the nose of the chuck and give the piece of wood one decent whack with a mallet.

It is a good idea to practice the motion of the whack beforehand, making sure you have room to swing the mallet: it is an awkward upward movement, and you want to get it right on the first whack.

 

[Gerald Lawrence]

Gord beat me to it . I had a Craftsman that gave me a lot of trouble and the wood and hammer were required several times over the years

 

[Steve Tiedman]

I had that happen once when the bit had a catch in whatever I was drilling (steel, maybe?). I stopped the motor, then tried to rotate the handle "upward" to retract the bit, and the chuck came right off the taper with the bit still stock in whatever I was drilling.

 

[Webb Willmott]

You sure it’s a Morse taper?

Yes

 

[Webb Willmott]

- Clean the male and female parts with mineral spirits or a very light lubricant (e.g. WD-40 or Boeshield T-9), then wipe to remove as much solvent or lubricant as possible;
- Open the chuck all the way so the jaws are fully inside the nose of the chuck body and insert the morse taper in the drill press quill;
- Put a wooden block on the nose of the chuck and give the piece of wood one decent whack with a mallet.

It is a good idea to practice the motion of the whack beforehand, making sure you have room to swing the mallet: it is an awkward upward movement, and you want to get it right on the first whack.

Should I polish the taper with some emery cloth also?

 

[Larry Copas]

Clean male and female parts with lacquer thinner or acetone. Put the chuck end in the freezer for 4 hours and warm the spindle end, then reassemble with a blow from the mallet.

If it comes apart again, re-clean, but this time put some fine valve grinding compound on both parts and reassemble. The valve grinding compound is an abrasive that locks the parts together. I used this trick on a Delta drill press that was used in production 40 hours a week, and it never came apart again while I was there.

 

[Don Wattenhofer]

Yes

Is it the kind that has a flat tang on the end ot the taper that keep the MT from spinning in the socket?
Someone may have used a chuck MT without the tang and then it could spin and damage the socket and the MT.

 

[Gord Cameron]

Should I polish the taper with some emery cloth also?

No, as long as the surface is not damaged, definitely not, just get both surfaces good and clean. You might be able to get one of the tools for cleaning the female taper ("Tapermate" was one brand) but you can probably do an adequate job with twisted paper towels soaked in solvent, and perhaps a toothbrush or shotgun cleaning brush or the like.

 

[Roger Wiegand]

Clean it thoroughly as others have said. Check for damage, any high spots will prevent it from seating properly. If there is corrosion or damage use a hand reamer to touch up the surface -- carefully! Using sandpaper or a file can make the problem worse, not better. The more closely the mating surfaces meet the better the joint. Very hard to maintain a perfectly flat surface using an abrasive with no solid backing.