drill problem

[avbill]

I was using the lathe to drill a 7mm hole in the blank. the drill bit is now total stuck in the drill hole. the hole is five inches long. the blank the acrylic. i tried reverse on the lathe.

i would like to save the blank.

any suggestions

thanks

 

[danom]

Hello Bill:
Becomes a tough situation. I have been there before and found that if I take the blank and secure it tightly in a stationary vise, and then take some vise grips and secure the drill bit. Then take some ice water and try to get it down along side the stuck drill bit. (ice water to possibly contract the drill bit) Then rotate the drill bit with vise grips anti clockwise to ease the bit out. Should you get lucky and get the bit out, then redrill blank as before only very slowly. You may save blank then
Dave

 

[OZturner]

Hello Bill:
Becomes a tough situation. I have been there before and found that if I take the blank and secure it tightly in a stationary vise, and then take some vise grips and secure the drill bit. Then take some ice water and try to get it down along side the stuck drill bit. (ice water to possibly contract the drill bit) Then rotate the drill bit with vise grips anti clockwise to ease the bit out. Should you get lucky and get the bit out, then redrill blank as before only very slowly. You may save blank then
Dave

When and if you can get the bit out, and are about to redrill.
Make sure your drill is sharp.
Take it slow as Dave suggested,
and more importantly, draw the drill back out to clear out the swarf.

5" is a deep hole, and even if you used a Parabolic bit you are generating more swarf, than the spiral can clear over that depth, so it has to be periodically withdrawn.
Hope you are succesful.
Brian

 

[Boz]

You may have to grind some flats on the drill bit so you can put a adjustable wrench on it to get more torque. If your blank is square I would secure it in the vice length wise to fully support the blank so it does not crack. The ice water idea is a good one. I would consider placing the bit in a cup of ice water and hold the blank up out of the water so only the bit is getting cold. In the future clear the chips out every 1/4 inch or less when drilling.

 

[walshjp17]

Been there. Done that. Best advice, as noted above, is stationary vise and vise grips.

Since the last stuck bit I have begun drilling a bit slower (no faster than 500 RPM), and pulling the bit out every 1/8" to 1/4" depending upon the material.

Also, if the bit starts getting warm, stop drilling for a few minutes to allow it to cool down. Hot plastic like to melt around metal.

 

[CHARLES STOPCZYNSKI]

Another alternative

Place drill bit along with the blank in a plastic zip lock bag, squeeze out what air you can. Put in the freezer for an hour. Take out, wood will warm much faster than drill bit (bit inside blank is insulated by the wood should stay colder longer), Place some scrap foam over bare metal portion of drill bit as soon as you take out of freezer, give it 15-20 minutes after removing from freezer, try rotating drill bit out.

Charlie

 

[Dick Mahany]

Great suggestions above.

I can tell you how NOT to do it.........My bit got stuck while I was pulling the tailstock back after drilling. The lathe was spinning at 500 rpm, the chuck taper popped loose, and I had the whole mess spinning. The chuck started whipping all over and the bit snapped. All of this before I could hit the stop button. I won't try that again. Lost one beautiful piece of amboyna burl and a very nice drill.

 

[raar25]

As with everyone else been there done that. The acrylic has melted around your drill bit. If the blank is not something which has alot of value to you I suggest using a hammer and chisel to break the blank away from the drill bit. I have also put the blank in a vise and used a pipe wrench to rotate the drill backwards. You may want to put the whole thing in the freezer for a few hours to help the plastic and metal free up and the plastic gets a little more brittle.