1/8 inch square hole in acetal

Will it work to use a 1/8 inch square broach, such as is sold by MSC, to
make a square hole in acetal (Delrin)? About 1/2 inch thick. Or will it
just tear up the acetal? I haven't worked with acetal. I'm reluctant to
spend 70+ bucks on a broach if it isn't going to work. Is there any other
way? I will have many of these to do.
Thanks for your kind advice.
Reply to
Will Self
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Will-it will work great. Bear in mind that square broaches, at least all the ones I've used, require a pilot hole slightly larger that the dimension across the flats. So you don't get a completely square hole. Each side has a little in the center removed. Use water or water soluble oil as a cutting fluid. Cheers, eric
Reply to
Eric R Snow
Would one of the less expensive square hole bits work? There are two kinds, one is a geometric figure with one less side than the hole wanted: three sided rounded triangle drills square hole.
The other is the woodwoorking item, an auger down the middle of a square hole shaving bit. 1/8 is very small for this. And you have to have the bit holder for your drill press model. I have one in 5/16.
The square broach, if you wish to spend the money, will produce good results. You may be able to press it with a drill press, but ideally an arbor press will provide more control.
Have you considered turning the end of a 1/8 square rod and pressing it into an undersized hole? Do you need a lot of torque resistance? You might spline the end of the rod on a lathe by moving the carriage by hand as a planer would move. Or is it a shaper? It's a shaper. I was wrong. Why don't I go back and edit that? Maybe I will. Ok, I'll just.....
Doug Goncz, Replikon Research, Seven Corners, VA Unequal distribution of apoptotic factors regulates embryonic neuronal stem cell proliferation
Reply to
Doug Goncz
Drill a smaller hole, then use a piece of 1/8 keystock heated with a torch and plunge it thru. Grip the keystock in a drill press to make the hole straight. IIRC most varieties of acetal handle remelting fine...
If the hole ends up oversize, for the next one make the keystock punch undersized appropriately.
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