how to remove plastic stuck inside core drill bit

Question

I use a 1/4" diamond tip core drill bit to make holes in the bottom of bowls to use them as plant pots with drainage. I bought the diamond core drill bit to drill ceramic bowls, however I also used it to drill 1/4" into plastic bowls, and this was a mistake. The plastic is wedged so tightly inside the bit that I cannot get it out. I have tried getting it out with an awl, a safety pin, a nail, a knife, etc. and no luck.

Any ideas? All I can think of is to secure the bit in a vise, and try to drill out the plastic with a smaller bit.

Answer 1

I would first try driving a screw into the plastic and then pulling it out. You could clamp the screw in a vice and pull on the bit so that you don't damage the bit with the clamp.

If it's tightly wedged in it might be easiest to drill out the center of it with the largest bit you have and then crack/break the rest of it out.

Answer 2

I'm not sure if there are any surefire ways to get it out, but I have an idea.

Put the bit into a bench vise, and then find a small screw or bolt that will fit inside the bit. Clamp down the screw with locking pliers and then heat it with a torch until it is red hot. Insert the end of it inside of the bit. Wait for everything to cool down and then try pulling the screw out.

You want to avoid heating the bit directly because that could cause it to lose its temper.

Answer 3

This just happened to me multiple times while drilling holes in the bottom of several large planters. I was able to use the blade of a box cutter to coax the plastic circles out of the bit. It had to be done while the bit was still hot. Running the first one under the hot water faucet helped.

Answer 4

Throw the bit in the oven or on the barbeque. The plastic will shrink as it heats up, and if you get lucky, you can melt it out. Otherwise you'll have enough room to get the awl/pin/whatever into it, and you'll have broken the suction.