Stuck Drill Bit

[walshjp17]

OK, possible bonehead move -- I'll give you that so I don't need lessons on how to properly drill a blank :wink:

I was drilling out a hunk-o-acrylic on the lathe using my dedicated blank drilling chuck and a drill chuck with an 8 mm bit inserted. I was going in about 3/4" at a time and backing out to clear the plastic but when I got to where I thought I would break through the bottom, rather than pulling out to clear, I pressed on and ... the drill bit caught and pulled out of the drill chuck! It is frozen in the blank. The good news: the hole is perfectly centered Bad news: the acrylic blank has a drill bit stuck in it.

I have tried to back it out with two different hand held drills set on reverse, tap it through with a nail set and hammer and twist it out with a set of vice grips with the blank in a vice. No luck whatsoever!!

Other than running the blank through the bandsaw close-aboard to the drill bit , does anyone have any thoughts as to how I can get the bit out while preserving the blank?

 

[Scruffy]

IN desperation..

WD-40? Freezing the whole glob?

Try cutting off the bottom first close to the drill see if that relieves enought pressure to start moving bit.

If all else fails, say a prayer of thanks for the inexpensive physics lesson and get out the saw.

 

[1080Wayne]

Drill bit in vise , vice grips on blank , all appropriate body parts crossed .

 

[Tom T]

I have had this happen also with acrylic.
Hubert were PMing about it yesterday, with True tone getting to hot.
Putting it I the freezer might work. As all the items would move.
What I did when this happened to me was. First question was it an expensive drill but. Because bending the bit is a option here.
I put the blank in the bench vise not to firm. My blank was square, so the blank itself would not allow the blank to turn. I the put the biggest pair of vice grips I had as tight as I could and proceeded to turn the drill bit back up. Then down a little than up. Up a little more than down. It took about 15 min but it came out. If the blank Israel cheap 5.00 or less cut the blank up tight to the bit and cut it off. The drill bit could break with that much pressure on it. I always wear safety glasses. Not saying this is the best method, but I have done it twice this way successfully and saved both the blank and the drill bit. Now I do not push drilling at all. One blank or two at the most then rest for five. Then another. Colt bit works the best wood river get hot really fast. Mine was 7 mm.
Oh yes Zip it.

 

[Curly]

The bit was hot enough to melt the plastic and they are now one. Cut away the blank and throw the bit and blob in a container of acetone to dissolve it. Next time lubricate the drill bit with a little dish soap in water. After drilling clean off the drill press of all water and lightly oil it to keep it from rusting. The blank can be rinsed with warm water.

 

[Tom T]

Thank you. I like that thought.

 

[walshjp17]

WD-40? Freezing the whole glob?

Try cutting off the bottom first close to the drill see if that relieves enought pressure to start moving bit.

Tried both with no joy. Upside, I now have a real nice 1/32" square of acrylic with a 8 mm hole in it to use in a segmentation project :wink::wink:

 

[walshjp17]

Drill bit in vise , vice grips on blank , all appropriate body parts crossed .

Arrrgh! Cannot get a good enough grip on the bit's shank to keep it from turning in the vice.

 

[Twissy]

You could try some heat. Drop the whole thing in a pan of boiling water for a few minutes then try the vice and mole grips.

 

[walshjp17]

I put the blank in the bench vise not to firm. My blank was square, so the blank itself would not allow the blank to turn. I the put the biggest pair of vice grips I had as tight as I could and proceeded to turn the drill bit back up.

Oh yes Zip it.

That did it!! :biggrin: Thanks, Tom. The drill bit finally broke free and i was able to wiggle it out. The oil suggested by Alan likely played a part as well.

Now, I need to get a light to see if the blank is worth salvaging, i.e., has the drilled hole been weakened enough to renderer it merely a 'lesson learned' or is it intact enough to attempt glueing in a tube. (Rhetorical question.):tongue:

 

[ed4copies]

Put the whole thing in the oven at 200-250.

About 10 minutes.
Grab the drillbit with a vice grip and put an oven mitt on your other hand, grab the blank. Back it out.

IT will work---I have tried (I mean, others have told me) often!!!

 

[tomas]

I would try heating the closed end with a hair dryer and then try backing the bit out.

Tomas

 

[walshjp17]

Alan, Wayne, Tom, Pete, John, Ed & Tomas:

Thanks for all your great suggestions. It looks like I was able to extricate the drill bit from the blank without damage to either. I now have lots of really good suggestions to try if I ever have another, similar brain f*rt. :biggrin::wink::biggrin:

We can close this thread now.