# Drilling bigger holes (HELP)



## PenMakerWillie (Nov 5, 2008)

Can somebody please help me. I ruined 5 blanks this afternoon trying to drill holes for a "valiant" pen. The tube sizes are 10mm and 12mm. Everything would be going great until the very tip of the bit broke through the bottom of the blank and that would cause my blank to bust off about a 1" piece off the bottom. It was very frustrating and I would rather not ruin any more blanks doing the same thing. Here's what happened and different things I tried:
#1 - Started drilling the 10mm blank and had it break a corner off
#2 - Same exact thing
#3 - Same thing, nothing changed. Made sure my speed was down, cleared the shavings more, let it cool in the middle, but still broke.
#4 - I tried pre-drilling with a smaller diameter bit. Once I put the 10mm bit back on it kept getting jammed. Ended with the blank breaking.
#5 - Started with the 12 mm only to have the same thing happen. This time I stopped probably every 10 seconds to let it cool, but it still broke. 

What am I doing wrong? :hairout:

Thanks for the help from the pros!


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## bill (May 21, 2004)

what type blanks?

On large blanks, I cut them over the size I need, this give a little cushion on the breakout

Keep your bits clean and sharp

I use a fast drill speed. Might not be right but I found for me, a slow bit catches more.


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## PenMakerWillie (Nov 5, 2008)

acrylics, I might move it up a notch but the 7mm would make bigger holes due to heat, that's why I have it turned down.


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## bill (May 21, 2004)

acrylics almost always break out a little on me, so I give myself room when I cut the blanks

are you using a drill press?


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## PenMakerWillie (Nov 5, 2008)

yes, I posted this same thing on IAP and somone mentioned to put another piece of material under the blank I'm drilling. Have you had luck with that?


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## speckfisher (Apr 11, 2006)

Im a machinist and usually small drill high speed and large drill slow speed.


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## speckle-catcher (May 20, 2004)

drill acrylics slow 

and definitely put something under the blank - it helps.

I also try to cut them long and drill from the middle of the blank towards the ends.


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## Fishin Tails (Mar 21, 2007)

I had the same problem with Acrylics. I went to Woodcraft and bought the Brad point known as the Pen Makers bits and have had really good success since. When you think you are close the the end go really slow.

Keep trying, you will get it. Once you do there is nothing hard about it.


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## Tortuga (May 21, 2004)

With acrylics I always cut them about a half inch long..and ALWAYS put a smaller scrap piece of wood below it for the acrylic to rest on. I use the 'vise' on the drilll press and it works out OK.. Skrewed up a bunch before I put the wood below.. Go slow at the end and keep clearing out the hole as you go. Accumulated shavings will shatter the end if you have a bunch in the hole.. Speedwise..I go full blast with everything. Just keep lifting and clearing as you go.


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## liftologist (Dec 8, 2007)

On acrylics I cut the blank long. I don't drill all the way through, I mark my bit to the depyh I want. Then to the bandsaw to cut off the excess. This really helps to keep the end from blowing and chipping out. Hope this helps!


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## MesquiteMan (Jun 28, 2008)

Speed up your drill press. Contrary to popular belief, faster is better in this situation. Don't believe me, give it a try! I drill everything at 2,900. I do not cut long and I do not use any water. I also do not put anything under the blank. I do clear the bit every 1/4" or so. I DO NOT have any blow outs EVER!


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## Fishin Tails (Mar 21, 2007)

MesquiteMan said:


> Speed up your drill press. Contrary to popular belief, faster is better in this situation. Don't believe me, give it a try! I drill everything at 2,900. I do not cut long and I do not use any water. I also do not put anything under the blank. I do clear the bit every 1/4" or so. I DO NOT have any blow outs EVER!


I have learned that Curtis is a pretty straight shooter. Saturday I went to the Garage, adjusted the belt on the Drill Press ( close to 2900 ) and drilled out four Acrylic pens. No blowouts or breakage. This really does work!


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## Bobby (May 21, 2004)

I drill all mine on the lathe and very seldom have a problem unless I set the blank wrong in the chuck.


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