# Drilling Acrylic Blanks



## Simsonicole (Apr 11, 2015)

Hi everyone...

Can anyone tell me what rpm is recommended for drilling acrylic blanks with a drill press?


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## longbeard (Apr 11, 2015)

I drill mine on the slowest speed. If I have more than a couple of blanks to drill, I will use water mixed with a little dish washing liquid in a spray bottle and lightly mist the hole as I'm drilling to keep the drill bit cool



Harry


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## WriteON (Apr 11, 2015)

I drill on the lathe around 900-1100.  Not sure if that is the suggested speed but it works for me. I might adjust the speeds up or down slightly as acrylics vary in texture.


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## ed4copies (Apr 11, 2015)

The sharper the bit the higher the RPM you can use.

Control heat---spray, use air, whatever you like.

I like about 1000 rpm, using water with a drop or two of  dishwashing liquid.  Lots of other ways work, too.

Don't drill through.  Stop an eighth of an inch before the end, cut off the end on a band saw.


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## TonyL (Apr 11, 2015)

I do the same as above...but have been leery about adding any type of lubricant. Do you find the need to rinse the blank before gluing?

As I feel the rpms slow and hear the first squeak, I withdraw the bit and let it cool for about 3 minutes. Sometimes I get a half inch a d sometimes an inch  - so far no lubricant, just sharp bits. I don't know if that is correct, but to date and after 300 pens, I only lost 1 blank while drilling (on my lathe); I got greedy with the my 2 "STOP" indicators.


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## KenV (Apr 11, 2015)

did anyone mention really really sharp bits --

Some bits are not sharp out of the package, and the lower the cost the better the chance they are not really sharp.

There are also bits sold specifically for drilling plastics -- and they differ in that they are not as aggressive and self feeding is reduced.  But they need to be kept sharp too.


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## flyitfast (Apr 11, 2015)

I use Colt Pilot bits after drilling a starter hole with starter bits.  I use water/soap to lubricate and cool.  I have been known to use non stick spray like Pam and then wash the hole out so epoxy will stick.  Speed of 400-500 and back out the drill ever 1/2" or so to clear the hole, although the Colt bits are better designed to self eject waste.
The key is to reduce heat and prevent the plastic from melting and "capturing" the drill bit (DAMHIKT!).  The Colt bits are a bit expensive, but they are worth it and stay sharp a long time.
gordon


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## TonyL (Apr 11, 2015)

Hi Kevin: I did mention...bought the TOL DD and love it! Make a huge difference.


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## Donovan (Apr 11, 2015)

The highest speed that I use is 750 rpm and go down to 450 rpm for 10 mm and bigger drill bits. I like to drill three sizes to give me 10 mm or bigger. I back out about every 10 mm to clear the shavings. 
If I have a few to drill I cool the drill with water and some dish washing soap

Donovan


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## Simsonicole (Apr 11, 2015)

TonyL said:


> Hi Kevin: I did mention...bought the TOL DD and love it! Make a huge difference.



Is that the Drill Doctor you are talking about? I do have one


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## Simsonicole (Apr 11, 2015)

I have a proper pen drilling vice to hold the blank in but when I get towards the bottom of the blank, the acrylic shatters


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## jttheclockman (Apr 11, 2015)

Well it has been suggested by someone earlier in this thread to drill and stop the drilling about 1/8" from the end and then cut off the remaining 1/8"

My suggestion is if you are having this problem and not all acrylics will shatter like that, but just CA a scrap piece of wood on the bottom. make it about 1/2" make it the same size as the blank being drilled. If the blank is round then just sand the scrap down to the shape of the blank. Now drill straight through or until you hit the wood.


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## Dale Lynch (Apr 11, 2015)

A waste block under the exit end.Ease it through the exit at about 1/4 rate as regular drilling.Or you could do like Ed said and leave your blank long then cut to length after drilling.

Waxing your bits helps reduce friction from the flutes which reduces heat.No need for water for me.I drill all my blanks,wood,stone,plastic,any combination of the three at the slowest speed setting with a very slow feed rate.

Only blow out I have had is from trying to hold it by hand.Took a chunck out of my finger so I don't do that anymore.


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## WriteON (Apr 11, 2015)

Forget to mention. I pre-drill with a 7mm and the move up to the desired mm. I also make the blank slightly longer in case the end pops a little bit.


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## Lucky2 (Apr 12, 2015)

Cut your blank in half, and drill at the slowest speed your drill press will go. Or, you can drill them out on the lathe, if you buy a proper blank holder. Oh yeah, don't use a lot of pressure when your drilling the blank, that's what causes your blank to shatter on the end.
Len


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## SDB777 (Apr 12, 2015)

I can tell you high speed and not clearing the 'waste' will result in out-of-round holes, melted acrylic, and blanks that are completely unusable!

I drill on the lathe...my lowest speed is 214.
Sharp drill bits that 'track straight' are a must....but the 'waste' should be cleared often.
You should 'hear' the drill bit making a smooth sound...keep the pressure smooth-n-steady, not forcing the bit to cut.  If the sound being made is more 'crunchy', then either too much pressure is being applied and/or the bit is dull....ease up and/or sharpen the bit.




Scott (don't blame the blank) B


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## TonyL (Apr 12, 2015)

Yes. The Drill Doctor. My experience with it has been very positive.


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## 79spitfire (Apr 12, 2015)

Sharp drill bits and stopping 1/8" short fixed my problems.


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## Lucky2 (Apr 13, 2015)

I don't know if this has been mentioned or not, but, when I first started out I always tried to drill the blank in one piece. I have quit doing so after a few blanks got ruined, to solve this issue, I started cutting the blanks in half and only drill one half at a time. You still need to use sharp bits, and not to high of a speed.
Len


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## Simsonicole (Apr 13, 2015)

I use the "pit" drilling method. This keeps the heat down and clears the flutes nicely. I think part of my problem is vice itself. Gonna have another try as I think I have the setting too tight as I was adjusting the wrong part  Also going to try stopping before I hit the end. 

Thanks for all the advice everyone! Trying it all...


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## Curly (Apr 13, 2015)

What is "pit" drilling? You don't mean "peck" drilling do you? Drill a little, stop and back out to clear the bit, drill a bit more, etc.


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## WriteON (Apr 13, 2015)

Simsonicole said:


> I think part of my problem is vice itself.



I was having all sorts of problems drilling.....I switched to Lathe Drilling. The failures are very minimal.


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## Simsonicole (Apr 15, 2015)

Curly said:


> What is "pit" drilling? You don't mean "peck" drilling do you? Drill a little, stop and back out to clear the bit, drill a bit more, etc.



:embarrassed: Hahaha...that the one. New it was called something like that ...but yes. That is the method I was taught.


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## Simsonicole (Apr 15, 2015)

WriteON said:


> Simsonicole said:
> 
> 
> > I think part of my problem is vice itself.
> ...



I was using the Lathe...but trying to slim line the process a bit so I didn't have to change out the chucks bits etc and had the drill press there...but I can never get the straight accuracy with the Lathe and it seems to heat a lot easier on the acrylics so I end up drilling a smaller hole than having to hand drill the hole to the right size when done on the lathe.


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## mmayo (Jan 25, 2018)

For years I have been drilling at my slowest lathe speed (500).  New Colt bits said 1000-3000 so I tried at 1000 rpm and of course cleared the chips often. Nice holes in both sides with no chip out. Both speeds yield similar results with acrylic acetate and alumilite. I started dunking the drill but in a cup of water while changing blanks. I wipe it dry and start the next blank with a cold, clean drill bit with perhaps a bit of moisture. More acrylics will be drilled at 1000 rpm’s.


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