Oh no not again

[WriteON]

Some things do not change.... Where's the dumpster bucket. However I'm saving this one. Will hit the bit with a micro torch ...heat it just enough to pull it out. The hole has be enlarged after extraction....Being the idiot I am the torch cost more than saving the blank is worth... but I need it anyway. Maybe I'll start to take more time drilling.... (have been saying that for over 10 years)

 

[sorcerertd]

Maybe I'll start to take more time drilling...

Patience is a virtue (that I don't have much of)

 

[egnald]

Wow that stinks. I think I've only had that happen once, but I was able to somehow wrench the bit out of the blank. - Dave

 

[jrista]

Some things do not change.... Where's the dumpster bucket. However I'm saving this one. Will hit the bit with a micro torch ...heat it just enough to pull it out. The hole has be enlarged after extraction....Being the idiot I am the torch cost more than saving the blank is worth... but I need it anyway. Maybe I'll start to take more time drilling.... (have been saying that for over 10 years)

Any chance you can put the blank in a vice, and use some rubber grip pliers to twist the bit in reverse to extract it without damaging either?

 

[Drewby108]

Any chance you can put the blank in a vice, and use some rubber grip pliers to twist the bit in reverse to extract it without damaging either?

Depending on material, yes. I'm guessing the problem here is that the blank heated enough to expand a bit until the initial bind, then cooled and shrunk to grip the metal like a tax collector on their money.

 

[Penchant 4]

NOT heat...that is most likely the cause of the problem. Put the whole thing in the freezer. The metal will probably contract more than the resin. No guarantee; but it has worked for me.

 

[jrista]

I would agree that cooling is probably going to be more effective than heating. Once tooled, back twisting it out should do the trick.

 

[WriteON]

Any chance you can put the blank in a vice, and use some rubber grip pliers to twist the bit in reverse to extract it without damaging either?

The 2 pieces are bonded....joined at the hip.

 

[WriteON]

NOT heat...that is most likely the cause of the problem. Put the whole thing in the freezer. The metal will probably contract more than the resin. No guarantee; but it has worked for me.

Pretty interesting and worth the time to try that.

 

[maxwell_smart007]

Wouldn't the torque of your drill press be enough to break it free? It must have melted and gotten in the grooves?

 

[TonyL]

Do you try https://www.amazon.com/Bostik-BladeCote-formerly-DriCote-10-75/dp/B00DSW7DWK

I buy it 3 or more at a time (from some other source...don't remember) and get it for about $18 or less a can. It is too late for that now, but I use it on every plunge.

 

[Penchant 4]

FWIW, for a long time I used Canola oil as as lubricant/coolant when drilling problematic (resin or sim stone) blanks. Flushing any residue out prior to bonding the tube was a pain (using smelly irritating acetone or lacquer thinner); and it was never certain that all of it was cleared. Discovered Anchor Lube ( https://anchorlube.com/where-to-buy/ ) and swear by it. A paste about the consistency of warm butter. Residue cleans up with water.

 

[WriteON]

Wouldn't the torque of your drill press be enough to break it free?

No... The lathe shuts down.

It must have melted and gotten in the grooves?

The pieces are united forever. I hate drilling a long acrylic blank... all goes well until the last 20%...and I know I should be more cautious when getting to the end. Some people never learn ... doubt if I'm going to try to save it. Mist likely will add to the Hall Of Shame bin.

 

[Jans husband]

I avoid problems like this by creeping up on the size of the hole by using smaller diameter drill bits before finally drilling out with the end diameter bit.
Also, regular withdrawal of the drill bit to clear the swarf is a good idea.

Mike

 

[egnald]

I've had the best luck using drill bits that are specifically ground for drilling plastics, but I still do a lot of the other things that have been offered here too. - Dave

 

[WriteON]

I avoid problems like this by creeping up on the size of the hole by using smaller diameter drill bits before finally drilling out with the end diameter bit.

That is the smaller bit.....was going to 3/8.

Also, regular withdrawal of the drill bit to clear the swarf is a good idea.

Mike

I should write that on the wall in front of me. This has happened a few times and I thought I was cured.
If the tail stock was not an M2 ..and threaded on... this might not have happened. The Chuck and tapered stem came out of the tail.

 

[Mike]

I think patience is the number 1 factor here and then a sharp bit. I have drilled only 8 or 10 acrylic/plastic blanks with regular twist bits and brad points but have not chipped or melted any of them. I know not all plastics are the same, some are much more difficult. I bought a drill doctor 750 about 15 years ago and never really used it much until I started turning pens. It does a great job.
I now use my Nova G3 chuck and a drill chuck in the tail stock on the lathe for drilling all blanks. I run the lathe 300 to 500 rpm and only go in about 1/2" and back out until I am all the way through. I also cool the bit with compressed air before it gets hot enough to smoke. I put a piece of masking tape on the bit a little past the length of the tube and go slower as I get to the end.

Mike