So.....acrylic will melt.

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LK&T

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Drilled out my first acrylic blanks yesterday and quickly found out you can generate enough heat to melt those suckers. I noticed it when the "feel" of the drill changed and the odor picked up a notch. BTW, the smell is atrocious. When I pulled the drill the chips were noticeably..... limp. No permanent damage done, and that blank is still perfectly useable.

When I drill on the lathe I pull the drill and clear chips often as a matter of practice. You know, like you're supposed to. Heat buildup when drilling wood has never been an issue for me. After the learning curve with the first blank I started pulling the drill often(er) and cooling it with the shop vac until it was about cool to the touch. This seemed to work fine. I even did a couple with a 6.5mm drill then went back and reamed with 7mm for the tube size, being careful all the time about heat buildup. Really couldn't tell a difference in fit, though. If I could I'd run the lathe slower, but 500 rpm is the minimum on my lathe.

So, questions! What are the tried and true tips and techniques for drilling resin/acrylic/plastic/whatever else blanks. Stopping and taking thirty seconds to cool the drill every time I pull it is a pain in the keister. I mean, that's an extra four or five minutes per blank. Ain't nobody got that kinda' time!
 
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jttheclockman

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Yes sharp bits. Drill at slow speed on lathe. or drill press. I use Denature alcohol to cool my bits and do clear hole often.
 

qquake

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Ed is right, I got a couple of blanks melted to the bit with some of my early acrylic pens. Pretty much ruined the bits and blanks. Then I tried cooling the bits by spraying them with water or wiping them with a wet sponge (with the drill press off, of course). But I heard some horror stories about hot bits shattering when sprayed with water. So I started drilling slower and clearing the warf often. Nowadays I use primarily brad point bits, and don't have any problems. Of course I still drill slow and clear often.
 

dogcatcher

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Get a plastic squeeze catsup bottle and fill it with automatic transmission fluid, the cheap ATF from the dollar stores. Squeeze a little on the drill bit as you drill to cool the bit and the ATF also works as a cutting agent. Cleans up easily, a little newspaper on the ways catch the drips. I also use the ATF as a wetting agent when sanding acrylics and the "resin acrylics". A little soap and water cleans the ATF off the acrylic.
 

MPVic

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Get a plastic squeeze catsup bottle and fill it with automatic transmission fluid, the cheap ATF from the dollar stores. Squeeze a little on the drill bit as you drill to cool the bit and the ATF also works as a cutting agent. Cleans up easily, a little newspaper on the ways catch the drips. I also use the ATF as a wetting agent when sanding acrylics and the "resin acrylics". A little soap and water cleans the ATF off the acrylic.
Now that's a new one - thanks for sharing.
 

jttheclockman

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Okay, I like the denatured alcohol idea. In a spray bottle?
No I use the cans. Just pour some on a shop cloth and set on top of bit after I release from hole. Cools quickly. One thing if you control the speed at which you drill, speed at which you advance the bit, use sharp bits, and clear the hole, the bits and blank should not get overly hot.
 

TonyL

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Tony - I'm curious, does the Dricote compromise the gluing in of the brass tube?
To date (over 5 years a few thousand pens), I never has an issue that I can attribute to its use. I so spray the bit entire bit during each plunge.
I use CA for wood, and epoxy for non-woods and hybrids. I don't use anything to clean the hole beyond blowing it out with compressed air to remove dust. I guess you can call the company. I often wondered about the lubricant interfering, but no evidence of such - i even paint the inside of the barrels without cleaning - no problems (yet! :))

I never tried DNA..I have it, and may try it if I run out of Dricote unexpectedly.
 

duncsuss

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I've found pink/red transmission fluid works well (also works as a lubricant when tapping threads).

And this is something I keep close to my lathe as a reminder to keep the bit cool ... yes, the bit fused itself into the acrylic acetate, and then sheared.

1207201958-01.jpeg
 

Niels

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I had it too today. The blank got completely out of shape cause of the heat. My lathe does not go slower than 350 rpm so I have to drill like that.

With what speed do you turn the blank to shape? I used to do it between 1500 and 2100 but I'm thinking now meaby to do it slower. Or does it turn less properly then?
 

qquake

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I turn at 2500 rpm, and drill on the drill press at about 900 rpm. About 20 years ago I had a blank or two melt and get stuck on the drill bit. But the bit was old and dull. Drilling with sharper bits and proper technique has eliminated any problems. I drill slower and clear the shavings often.
 

Niels

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Ok thanks. Do you think turning on let's say plus 2000 speed gives better results then 1500? Meaby the speed also adds to the smoothness of the turned blank?
 

egnald

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Even though it is pretty expensive, I use Bostik BladeCote (formerly DriCote) from WoodCraft as a lubricant on all of my drill bits. I think it really helps a lot. With some of the more brittle plastics like Inlace and Rhino blanks, I also dribble a little denatured alcohol in the hole as I am drilling. I keep my denatured alcohol in a plastic squeeze bottle with a Yorker Spout type of cap (WoodCraft WoodRiver Liquid Storage Container, 12 oz.) - Dave
 
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