drilling Acrylester blanks

[MURPHY101]

Hi Folks, this will be my first time trying this so be patient. I have a
>problem drilling acrylester blanks ordered from woodturningz.com. Its
>probably finger trouble on my part but the blanks shatter when i have
>drilled 1/2 way into the blanks. I clear the swarf frequently and have tried varying
>the speed but results are not great. Any suggestions would be appreciated.
>Richard Murphy
>

 

[ed4copies]

Welcome Murph!!!


Six months and four posts - come outta your shell a little, man!!!

OK, to your question:
Acrylester is very brittle. But it should not give you THAT much trouble. Drill around 1000 rpm (+ or - 400 is fine). Make sure you are holding the blank so it can't vibrate. A wood hand clamp will work - but support as much of the blank as you can.

Dump out the shavings every half inch (12mm) or so and add cool water to the hole. Spritz your drill bit with cool water, too, if you want to play even safer.

DON'T ATTEMPT TO DRILL THROUGH!!! Stop about 5mm from the end and cut off the remainder on your band saw to expose the hole. Acrylester LOVES to SHATTER as your bit EXITS!!!!

TURNING the blank is ALSO a challenge - VERY SHARP tools and CAREFULLY remove small amounts.

Good luck and feel free to send me a plane ticket -- I'll stop in and show you how. (Oh, PR-Princess will require passage, as well - she would shoot me --an American phrase -- if I left her behind!!)

 

[mg_dreyer]

I have had a lot of experience blowing out blanks (usually at the end when I don't follow my own advise) so here goes just some ideas.

First I usually never drill all the way through the blank. I drill until I know the tube fits in with some clearance, glue the tube in and then either cut off what I did not drill or simply sand it off.

Clearing the debris often is important. You also need to consider heat build up. I usually drill down a little on numerous blanks then take the next part out and rotate. If I need to cut quickly I have water in a squeeze bottle (from any scientific supply company) and add water in the holes as I drill (NOT ON WOOD).

Go very, very slow.

Usually middle blowouts are from not drilling straight. Consider a jig to hold if you cannot. I generally hold the blank in a wooden jig that keeps it relatively straight.

Finally - I find acrylester the hardest stuff to work with if you do not go slow.

Hope this helps.

 

[mg_dreyer]

Just to be clear Ed posted at the exact same time as I did - I am not copying his post!!!!!

 

[keithkarl2007]

finally a fellow irish penturner, welcome to the forum

 

[ed4copies]

Just to be clear Ed posted at the exact same time as I did - I am not copying his post!!!!!

Fast fingers help!!! Beat you by THREE minutes (or some part thereof!!)

 

[cnirenberg]

Don't feel so bad...40 posts or so in 4 years.. Oh well.
Have you tried drilling blanks using your lathe? I have a mistake of a drill press which seems to make a better lampstand. Haven't had any problems using the lathe yet.

 

[ed4copies]

HI CRIS!!!!!

The lathe will do most of the things we are suggesting. Your scroll chuck gives GREAT support and will not allow vibration and you USUALLY will insert the bit in the center, since the blank is spinning and the center is well-defined. So, yes, the lathe is a GREAT answer!!!!

Speak up more often, Cris ----

 

[jkeithrussell]

The only thing I can think of to add that what has been said already is that your drill bit needs to be sharp. With all the trouble you are having, this could be the case.