whatwheel

How do you drill a hole in plastic type materials without cracking them and do not have a drill for plastic?

Thanks, whatwheel.

proptop

My Feedback: (8)

Well...at least part of it would depend on what size hole and what type of plastic.

I would, for example, start out with a pilot hole that would typically be much smaller than the finished hole diameter. Work my way up in stages, until the final dia. is attained.
Take it slow, and try not to get too much heat build-up...variable speed drill would be very nice to have.

A drill that is sharpened for wood should also work O.K. for plastic.

RCVFR

My Feedback: (7)

On thinner plastics, I generally run the drill bit in reverse. It is slower, giving you more control and doesn't tear the plastic as a forward drill might. On thicker plastic, I start out with a reverse cut, then go with a forward cut after a hole diameter has been established. I use a backing material when drilling plastic so as to allow drill pressure wthout damage.

Gray Beard

My Feedback: (-1)

I use dental burrs and not drill bits. You can buy small burrs at your local dremel supply store. Normal drill bits tend to rip plastics and fiber glass apart.

whatwheel

Thanks for your replys, I have a set with two types of bits not used yet, one type is high speed steel, the other must be for wood as they hane sharp spikes on the ends and half the number of twist that the HSS has. I will be drilling a hole about the size of a prop shaft. If I use the wood type should I go for it in one shot? or drill a small hole first?

Thanks , whatwheel.

eagle1945

apply a layer of tape on either side of thinner plastic and never dril a hole over an 8th inch. grind or sand the hole to the desired size. for thicker plastic I've had good luck using centering wood bits, they cut the outside circumfrence and then cleans out the hole. try to do all drilling against a solid backer.

Lnewqban

whatwheel,

Use the bit with sharp spikes on the ends and drill one small hole first, which should have a diameter similar to the central spike of the bit.

Now, if this hole needs to be drilled in a propeller, a drill bit is not the recommended tool.

whatwheel

Sorry, I should have said what i am going to drill. I w

ant to drill a plastic degree wheel so it will fit on a prop shaft for timeing.

Thanks.

Gray Beard

My Feedback: (-1)

Pilot hole then a prop reamer.

kwblake

The most important thing with drilling plastic is to have some backing. If you are using a drillpress, place a piece of wood or something under the piece you are drilling. Make sure the piece is clamped to the table, and go easy with the pressure. Most plastic or plexiglass will crack when the drill breaks through the backside. A little coolant, or water would not hurt.

ron ward

 the best way is with a dill press so you can contro; the feed speed. if you can use a press, then the type of bit is not all so important as long as it is a fluted, high speed type bit. a brad point in the above post will work fine.  the idea is that by hand, the bit will grab when it breaks through the bottom and might break the plastic. backing is definatly needed in both cases and the piece should be kept down tight on the backing. if possible, the most reliable way is to sandwich the plastic between 2 pieces of wood and drill through the whole shebag, as long as you can accurately locate the hole center with the piece of wood on top.