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Anyone have any suggestions for drilling acrylic blanks? Do I need some plastic bits? How about those colt bits? They look good but there are mixed reviews out there. Sorry to shotgun blast the questions.
 

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+1 about going slow.

I have Colt brad point bits, with the double spiral. I have only used in wood. I like them.

I also have Colt Maxi-Cut Forstner bit, also only used in wood. I LOVE these.

The reason for going slow is to minimize heat. If too much heat, the acryllic will melt rather than cut and you will not like the result.

I would experiment if possible on a scrap piece, to test type of bit, feed rate etc.

I would also slow down the drill press to about 500 rpm.
 

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Even with the drill press at its lowest setting I've had blanks blow out due to heat build up.

My method:

1) never use brad point bits
2) slowest setting on the drill press
3) only advance the bit 1/4 inch into to blank before backing out
4) use WATER -- I have a few syringes I fill with cold water and dribble into the hole, each time I back out the bit I fill it up to the top with more water

You need plenty of paper towels, and there can be a little spray -- but you were wearing your safety glasses anyway, weren't you :yes:
 

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The New Guy
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I normally do it on my lathe, at about 500 rpm. Slow and steady, back out to clear debris often and you should get a nice clean hole.
 

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Woodcraft sells a great bit. I believe they are Woodriver brand. Brad point bits are a must as they prevent blowout, especially in acrylic. Hope this helps.
David.
 

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Go slow,Back out often,keep tools very very sharp.....I even take breaks and go do something else to let the blank cool down. Heat is is NOT your friend.
 

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Drilled over 100 acrylics, some guys go over kill with suggestions, literally sharp bit eject frequently, don't need to use water nor take a break, your bit or blank would hear would NOT heat up if you drill slow and eject your chips SIMPLE , brad point bit, never had one crack
 

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Old School
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Lotsa good suggestions so far. I would only use blanks that are cast acrylic, not extruded. They look the same, but machine differently. I agree, any sharp drill bit will work if used slow. If you have a drifting problem at the start, place the bit to the mark and turn the bit backwards for several turns just to make a starting divot.





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Hi All
Thats the secret go at a slower n steady feed on the drill press I found doing it on the lathe was not that successful unless you have the right chuck jaws to hold your work peace nice n square.
Good Luck
Huey
 
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