Drilling Acrylic/Resin Blanks

[angelo49]

When drilling these blanks there is always the risk of a blow out when the drill exits thru
the bottom of the blank.
FOR ME IT'S ABOUT 90%, NO MATTER WHAT DRILLS I USE.
So I cut the blank much longer than needed and drill past the tube length.
Then cut the blank to length and you end up with a fully drilled blank.
But you might end up with an unusable cutoff.
Now I cut the blank slightly longer than tube lenght and medium CA glue a piece
of any wood about 3/4'' in height to the bottom of the blank.
Drill untill you enter the wood, then cut off the glued piece and you're done.
This doesn't take much time at all. I don't remember where I got the idea from, but I'll
do this from now on.

 

[Penpal]

Why not use any device necessary if you save all your blanks.

Peter.

 

[Woody]

Nice one Angelo I always cut my blanks longer than needed and cut the extra off after but as you say sometimes whats left is of no use

 

[Vic Perrin]

I must have drilled a hundred or more acrylic/resin blanks and you can count the number of blow outs that I have had on one hand. I cut the blanks just over the length of the tubes and drill straight through. I always drill on the lathe with a set of pin jaws. The drills I use are nothing special in fact they are the cheapest that you can get from UK drills. Whist drilling I retract the drill very regularly to clear the swarf. I drill at relatively low speed and the hand feed rate from the tail stock I make sure is very steady. Just before break through I slow the feed rate of the drill . I can hoestly say that I don't find it a problem.

 

[edlea]

I blew the brains out of one the other day. .normally with very careful drilling I succeed but this time I was thinking of something else and forgot that I was nearing the end

 

[Buckeye]

I never get blow outs and I only cut the blanks just slightly longer than the tube. What I do is mark the drill bit so that it has a mark the same length as the blank and as I am getting near to the end of the blank just ease back on the pressure and no dramas no blow outs.

Peter

 

[Vic Perrin]

I never get blow outs and I only cut the blanks just slightly longer than the tube. What I do is mark the drill bit so that it has a mark the same length as the blank and as I am getting near to the end of the blank just ease back on the pressure and no dramas no blow outs.

Peter

 

[Bammer]

I hope Davey Gee reads this ...

 

[GSteer]

I never get blow outs and I only cut the blanks just slightly longer than the tube. What I do is mark the drill bit so that it has a mark the same length as the blank and as I am getting near to the end of the blank just ease back on the pressure and no dramas no blow outs.

Peter

Pretty much the same here. I'm still in low numbers of blanks drilled (<50) but the only blow out I've had was cross-cut black palm. It caught right on the exist and kaboom, tis all a learning process. Can't say I've had any other issues but I'm rather a cautious driller letting heat dissipate as required.

 

[angelo49]

It's probably better in a 4 jaw chuck on the lathe, but I hold the blank
in a drill vise and use a drill press. The vise is only clamping on 2 sides.
I have several 4 jaw chucks but none of them are scroll chucks.
These are independent chucks, you have to dial in each jaw separately.
That's a real PITA
I should get a scroll chuck, but................

 

[angelo49]

I hope Davey Gee reads this ...

What's So Funny?

 

[rayf6604]

It sounds to me that you're drilling polyester blanks, and I've had the odd one blow out. Polyurethane or alumilite is much more forgiving. As Vic said, I rarely have a problem, my solution is drill from both ends.

Sent from my SM-G928F using Tapatalk

 

[wm460]

Smart thinking Angelo.

 

[Lons]

I'm the same as the others and never have a problem. Use the lathe and chuck and my drills are nothing special but they are sharp and I drill carefully. Blanks are always a little oversize and I always drill straight through, it's easy to feel and hear when the drill is nearing the end but I mark the drill anyway with marker pen and just wipe the mark off with cleaner when finished.

 

[Penpal]

I use DeWalt Type 2 drills with nigh on 100% success for thirty years.

Peter.

 

[Twin Oaks]

FWIW, PSI has new bits out for drilling plastic only.
(PSI= Penn State Industries)

They are not cheap though.
Penn State Industries: Product Search

 

[GSteer]

They look interesting for problematic materials, although I won't be jumping about to replace my normal bits. Does anyone know what that particular shape of tip is called?

 

[Terry Q]

Angelo I only use a drill press for all my blanks. I make sure I clear the chips FREQUENTLY. I also back with scrap wood.

 

[Penpal]

FWIW, PSI has new bits out for drilling plastic only.
(PSI= Penn State Industries)

They are not cheap though.
Penn State Industries: Product Search

I missed the value and exact shape of the drill in that its very expensive compared with others., the tip is blurry.

Peter.

 

[hawkeyefxr]

As the drill emerges from the blank it acts like your cutting brass,it try"s to pull it's way through, the acrylic blank cannot take this stress as the drill pulls it way through and it gives way where it's unsupported with a resulting chunk of acrylic being knocked out..
Set a drill depth stop, i am lucky in that i have one built into my drill, most have the threaded stop on the side with two nuts. I set it so it stops about 3mm from emerging then use my 12in disk sand to sand away the blank from the blind end still it meets the hole.