Drilling Inlace Acrylester

[Ben Richardson]

Having made a bunch of wooden pens I have decided it is time to try the plastic types. The first time I tried to drill the blank it popped out at the bottom. I know you can't drill very fast with the plastic but even going slow it popped. I am using a brad point drill that is in good shape. What do you think I am doing wrong. Any pointers happily excepted.

[robert hainstock]

I try to have a piece of board under the blank, but I also try to cut the blank long if I can. If all else fails, save the pieces for regluing. :eek::eek:
Bob

[David Walser]

Ben,

Did you have a backer block supporting the bottom of the blank? If not, try that. It should prevent your drill from blowing out the bottom of the blank.

Another approach is to drill half the way through your blank and then flip it end-for-end to finish drilling. I've not tried this second approach -- I've always been afraid I'd not get the two holes lined up perfectly. I've heard other turners say it works for them.

Good luck and hope this helps.

[Jack Mincey]

I've only done a few, but the directions I got where to cut the blank a little longer than you need and drill just short of going through at the bottom and then cut that end off. It worked on the one's I've done.
Jack

[Ben Gastfriend]

On acrylic, I always cut the blanks about 3/8" longer than needed, which usually is availiable in the full pen blanks, then drill to a depth where you leave a couple 16ths of a inch at the bottom not drilled through, then band saw the end off exposing the thru hole. Works for me rather than buying 2 blanks per pen order, just incase one blows out.

[Dennis Peacock]

Acrylics need a backer at the bottom end to aid in blow out prevention. I used to do a lot of acrylic pens. Use a standard twist drill bit, a sharp one is preferred, and slow RPM at the drill press and empty the chips out very frequently to prevent heat buildup in the pen blank.

[Bernie Weishapl]

I agree with Dennis. If you are going to cut them to length then put a backer board on the bottom. Also I have found that brad point bits give me fits with acrylics. I use a sharp standard bit to drill. I now cut my blanks in half and then like the other drill to within 1/16" of coming thru then cutoff to length at the bandsaw.

[Ben Richardson]

Thanks for all of your responses. I think that I will get an 8MM twist drill and only drill close to the end then cut it off. What kind of glue do you use? I had a CA glued tube slip out while cleaning off the top.

[Greg Ketell]

CA works fine; I use thick. Make sure to rough up the tube first. I use 80 grit sandpaper.

What kit are you using that you are using an 8mm bit? The slimline family all use 7mm bits.

Speed of drilling isn't the key, it is frequent clearing so the pieces don't start rubbing on the side of the blank causing heat build-up. That will cause no end of trouble. I clear the bit every 1/4" at most and 1/8" near the end. And I will often allow the blank to cool a minute or so before doing that last little bit. I've only ever had one blow out on me. My friends all do the "cut long, drill, cut off" method.

GK

[Brian McInturff]

I do almost exactly the same as Greg. But, I do use slower rpms on the drillpress than I do for normal pen blanks. Same goes for some of the exotic woods like Afzelia. I usually end up stopping the drillpress a couple times during the drilling to let it cool off. I had one once upon time smolder while in the ress. Smoke came billowing out of the blank and it stunk to high heaven. I learned then to use really sharp bits. Get a Drill Doctor and if you do a bunch of pens then several bits of the same sizes for your favorite pen kits.

On acrylics you need to make sure you don't get "bit wander" in the blank. Otherwise you need to use a good amount of glue to fill the void. I use a disk sander and a mitre guage to clean the ends up and keep them square.

[Greg Ketell]

Bit Wander, that is a good point. A friend of mine was having tons of blow-outs. We finally figured out that his drill press was "sloppy" which allowed the bit to wander more at the bottom of the blank than at the top. He replaced his drill press and has no more problems.

To test your drill press: Chuck up a nice big fat bit. Extend the quill all the way to the bottom and then retract it 1/4" or so. Grab the bit and shake side to side. If the bit moves in reference to the table then you have an issue. Small movements are "ok" but big movements are bad. One Harbor Freight "professional" drill press had over 1/8" of travel. And that was brand new on the showroom floor.

GK

[Bernie Weishapl]

Ben I use 30 minute epoxy when I do acrylics. Haven't had a failure yet. I had a couple fail with CA but it could have been me or the glue. Don't know.

[Jon Lanier]

Use a backer. But also go slow and short. Meaning go a little ways down and bring it back up to clear debris and repeat until through. If acrylic is not cleared out it can blow out.

[Don Eddard]

I use sharp standard (not brad point) twist drills on acrylics, also using a backer board and the "slow speed and clear often" approach, and so far (knock on plastic) I've not blown out an end yet.

I'm also in the epoxy camp for gluing the blanks to the tube.

[Paul Douglass]

Just a suggestion, I haven't done any plastic, but I do this often on wood. I set my drill press so it drills deep enough that just the point of the brad point bit gos through the end , just far enough that you can see the small hole so you know where the center of the hole is. Turn the blank over and drill the end out using the small pin hole as a starting hole for the bit.

[Ben Richardson]

I am using the "Click pen" kit from Pennstate Ind. One of the few that has a click pen action

[Horst Hohoff]

Hello,
I drill my pen blanks on the lathe and do it from both sides. This prevents any kind of blow out.

Horst