Charles in SC
Well Known Member
I have read the threads on this but I am wondering if it should be done with a high or low rpm and or high or low feed speed. Also what about a lubricant?
thanks!
thanks!
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Plexi drilling question
- Thread starter Charles in SC
- Start date
Plexi Drilling
A few tips:
1. Use plexi drill bits. Tiny Dremel bits (in a Dremel tool) can be used for pilot holes (at high speed they basically melt their way through).
2. Make sure the plexi is warm (same tip as for trimming the plexi).
3. Rotational and feed speeds vary with bit diameter; what you're looking for is a "shaving" effect that produces an extremely thin curl of plastic. When I have the right speed the shaving curl coming off the plastic is continuous/nearly continuous. I don't use a lube.
4. Debur carefully...it's just as easy to start a crack with poor deburring as it is with the hole itself.
Good luck,
Mike
A few tips:
1. Use plexi drill bits. Tiny Dremel bits (in a Dremel tool) can be used for pilot holes (at high speed they basically melt their way through).
2. Make sure the plexi is warm (same tip as for trimming the plexi).
3. Rotational and feed speeds vary with bit diameter; what you're looking for is a "shaving" effect that produces an extremely thin curl of plastic. When I have the right speed the shaving curl coming off the plastic is continuous/nearly continuous. I don't use a lube.
4. Debur carefully...it's just as easy to start a crack with poor deburring as it is with the hole itself.
Good luck,
Mike
pmccoy
Well Known Member
I also used the plexi drill bits and didn't have any issues. However, when it came time to put a few countersunk holes in, I had trouble. I ended up cracking my canopy on several of the holes when I was using a countersink bit with a pilot. I called up Avery tools, and bought a 'chatterless' bit without a pilot and didn't have any more problems. For the holes that I cracked, I ended up drilling them out larger, till the cracks were gone.
Rick_A
Well Known Member
Good backing
Even with a plexi bit it is very easy to crack the plexi. Definitely practise on scrap pieces before you try to do it for real.
I also found that having a piece of wood under the hole you're drill is essential. You want to do your best to not let the material grab the bit, this will definitely cause a crack.
Even with a plexi bit it is very easy to crack the plexi. Definitely practise on scrap pieces before you try to do it for real.
I also found that having a piece of wood under the hole you're drill is essential. You want to do your best to not let the material grab the bit, this will definitely cause a crack.
Charles in SC
Well Known Member
Thanks for the info, do you use a solid piece of wood to back it up or is there a hole in it?
I used Plexi bits...
... with no lube and had no trouble whatsoever. Also used standard piloted countersinks... had no trouble there either.
One tool that came in handy for me was the 100 degree conical rotary grindstone from Perma-grit. Expensive little devil, but one of the few things that works if you forget to c'sink before you enlarge a Plexi hole to 5/32, which means a #30 piloted c'sink would rattle around in the too-large hole. THAT is recipe for a big crack.
... with no lube and had no trouble whatsoever. Also used standard piloted countersinks... had no trouble there either.
One tool that came in handy for me was the 100 degree conical rotary grindstone from Perma-grit. Expensive little devil, but one of the few things that works if you forget to c'sink before you enlarge a Plexi hole to 5/32, which means a #30 piloted c'sink would rattle around in the too-large hole. THAT is recipe for a big crack.
Rick_A
Well Known Member
Use a solid piece. The idea is stop the drill bit from being pulled thru the material - which can happen in the blink of an eye.
Another great tool to use on plexi is the Zero Flute Countersink - like the one shown on the bottom of this page: http://www.aircraft-tool.com/shop/search_result.aspx
I only found out about these after I was done with most of my plexi & fiberglass countersinking. The first time I used it, I was wishing I had known about them when I started on my canopy.
I had no problems drilling with the plexi bits but absolutely agree with the others about not using a standard c'sink. Mine grabbed on several different holes and put some small cracks in the hole wall that had to be enlarged to remove. Either use the zero angle, the perma-grit or at least one that is dull so that it does grab and try to screw itself into the material
frazitl
Well Known Member
My advice
is to use fairly high speed and very low pressure with plexi bits. Solid hard wood backup is good. Practice a lot on some scrap. Try to make it crack the plexi to get a good feel of it. If you need to enlarge the hole (say for the slider canopy latch), use a high quality step drill (uni-bit). One hole or chatterless countersinks worked well. I waited 'till I had 100 plus temps to do this work and the BIG CUT (easy in Vegas). Be sure you have enough extra hole diameter to allow some movement around the screw+dimple major diameter. To be extra careful, I countersunk the holes deeper than the dimples in the aluminum caps required so that the plexi can move around without binding. I made an aluminum cap for the front of the slider so I could carry this technique out throughout the canopy. No cracks yet, but then maybe I'm just lucky...
is to use fairly high speed and very low pressure with plexi bits. Solid hard wood backup is good. Practice a lot on some scrap. Try to make it crack the plexi to get a good feel of it. If you need to enlarge the hole (say for the slider canopy latch), use a high quality step drill (uni-bit). One hole or chatterless countersinks worked well. I waited 'till I had 100 plus temps to do this work and the BIG CUT (easy in Vegas). Be sure you have enough extra hole diameter to allow some movement around the screw+dimple major diameter. To be extra careful, I countersunk the holes deeper than the dimples in the aluminum caps required so that the plexi can move around without binding. I made an aluminum cap for the front of the slider so I could carry this technique out throughout the canopy. No cracks yet, but then maybe I'm just lucky...
