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Discussion Starter · #1 ·
I'm building an oil bunker for my tender, and trying out a common technique that I've never used before. Namely, inserting small brads to represent rivets.


Trouble is, even at the slowest speed, my Dremel melts the plastic, which ends up making the holes much wider than the drillbit. Plus I have to keep stopping and scraping the gunk off the bit. I can put the bit in a pin vise and that works fine but is way, way, too slow!


So how do you drill a bazillion tiny holes in styrene without melting the plastic or going crazy?
 

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I would also recommend the use of "wood bit" rather than the common metal piercing drill. The outer cutters stop the ABS from cracking. and personally I use a wheel brace as it is very slow, with practicaly no torque and you can "feel" the hole as it is cut.

regards

ralph
 

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I've found the best way to be a pin vise.  It's time consuming, I know,  but I seem to get good results.  I use a ratchet type pin vise that makes it go a little faster, but it still takes time.  Just find a good show on tv, sit back and drill.  
Dan
 

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I use a Foredom Flexshaft; with a number 30 hand piece.
All the Dremel tool bits are copies of this system and will work in the Foredom, cutters, grinders, burrs and even small polishing wheels

Variable speed, foot controlled Foredom flex shaft, other than an occassional new flex shaft and motor brushes...30 years of service! Worth every penny. Excellent Jacobs chuck that can hold bits as small as # 70 (0.028"). Can also hold a pinvise with an 1/8 inch shank for even smaller bits.
Yes they are more expensive, but considering how much we pay for 'toys' it is easier to justify. Specially with better results. The foot control gives you your hands back!

Drilling tips; use beeswax as a lube, drill a block of wax before drilling your holes, the bit warms and the wax melts keeping chips out of the flutes. Back styrene with wood, will help with keeping tip clean and keeps backside of hole cleaner. Sit so you have arm rests near the workpiece, fine bits are fragile and will quickly snap with lateral forces. When drilling metal back out ofen to clear waste and use plenty of wax. Beeswax is sticky enough to stay on the bit at high speed, can also be used to hold parts in set up. At slow speed you should be able to lift a whole ine of styrene out of the hole, no more bit cleaning.

I haven't priced them lately, but I bet it will get more use than a $300 rail bender... that's one I'm having trouble justifying!

This comes from 25 years at a jeweler's bench, trust me breaking a bit in a hole was an expensive proposition to be avoided!

John
 

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Very sharp drills and plenty of feed. If you go in to slow then it has time to warm up.
 

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Ray,

Have you tried pushing the brads in with a hot soldering iron? They make their own holes!

Alternatively, you need a speed control for your drill. I have a Micromark "jewellers drill press" which makes life a bit easier, as it isn't a super-high-speed device like the handheld Dremel. And it can be slowed even more with a motor speed control, like the ones sold for fans.
 

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Slow speed is definitely the answer. I've got a Minicraft 12 volt set which runs much, much slower than the Dremel. It's perfect for drilling plastic. I've got a battery-powered Dremel which also goes fairly slowly, mostly because the motor doesn't have the torque of the Minicraft ones, and slows down when working through the plastic.

Later,

K
 

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Discussion Starter · #11 ·
Thanks for the suggestions! The Dremel is variable speed but still too fast. It would be ok if I was just drilling through a sheet of styrene, but the corner joints are all reinforced with square stock.

I found that my regular Black & Decker drill goes slow enough to do the job. I just have to be very careful to keep it straight, as it's easy to snap off such a thin drillbit.

A drill press sure would be handy.
 

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Ray
If you would grind a slight flat surface on each of the drill bit flutes you will find it will work much better in plastic, this flat flutes will now cut like a spade bit in wood, and it will not grab or try to pull through as it exits the back side. I would suggest you might try the abbrasive stone on your dremel, I know you are using a small bit, I would recomend a good pair of magnifier eye glasses to see your flutes. Good luck Dennis
 

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A drill press sure would be handy


Ray,
There are quite a few rigs sold for full-size drills to make them into a drill press. Not great compared with a true press, but good enough for your job.

I recently bought a massive table-top 1/2" drill press for $99 from Home Depot.

Final thought. If you have one of those cordless screwdrivers, there are sets of drill bits available from B&D with hex shanks to fit the quick-release drills and the driver/drill version. A cordless driver/drill running in screwdriver mode will operate very slowly. I use it for drilling soft wood and plastic all the time.
 

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harbor freight sells those bits cheap and micromark makes a chuck with the hex on it that works great with the little bits .....

plus if you are working on something that has several sizes you can set several up and just plug in the one you need .....
 

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I found that no matter how hard I tried I could not drill a row of holes straight or equally spaced. But one day I decided to use a scrap of perf (circuit) board as a template. I drew a line, taped the perf board to it and drilled away with my pin vice. The holes came out equally spaced and perfectly straight.

I also used a 3 volt, battery powered, Black and Decker screwdriver for drilling. They turn nice and slow. Unfortunately after the battery finally died, I failed to replace it.

Sometimes the drill bit used with the perf board is too small and I wanted to enlarge the holes. I found by incrementally increasing the size if the drill bits, I could enlarge the holes and maintain the accuracy of the spacing and line.
 

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Ray, I agree with John. I bought a pin vice that work with a corkscrew motion to dril, and it works great!

Paul, for some reason I cannot quote you, but the PC board idea is great! Thank you for posting!

Matt
 
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