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Old 03-19-2018, 09:16 PM
Bavafa Bavafa is offline
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,069
Default Drilling the canopy

In drilling the canopy, I used a drill bit for plastic (118 tip) from McMaster with not so good results. When looking at the holes with a magnifying glass from inside, on some of the holes there is a chip on the exit point. (I have deburred the holes which has taken roughly 70-80% of the chip out but not all. From what I can think, here are my options:

1- Deburr more to take all the chip out but it will make a semi (small) countersink on the inside
2- I can use a Plasdrill bit which have had great results with but they are not available in the number sizes and 5/32” would be my next size which makes my current hole of #27 to a 5/32” hole.
3- Don’t be picky and leave it as is
4- Your suggestion
5- Your recommendation

Thanks in advance
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Old 03-19-2018, 09:32 PM
elev666 elev666 is offline
Join Date: Feb 2013
Location: Kincardine Ont,Can
Posts: 118

It's been a couple years since I did my canopy but my initial holes were all number 40 and then any holes after that you want to have a backer made of wood or UHM , if you need to use one of your regular bits you can dul them by drilling into your concrete floor for 10-15 seconds and the only thing you can use it for now is plexi
Give your glass all the room you can to expand & contract ,,, 2 Of the 4 RVs in my county have cracked canopies rite now , fingers crossed every time I close mine these cold mornings !
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Old 03-19-2018, 09:37 PM
RV3Bob RV3Bob is offline
Join Date: Jan 2008
Location: Los Altos, Ca.
Posts: 28

Find a scrap piece of canopy. Get a brand new uni bit and practice with it. I have found it works the best. Nice clean hole and it de burrs.

Bob Grigsby. Los Altos. Ca
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Old 03-19-2018, 09:56 PM
DHeal DHeal is offline
Join Date: Sep 2006
Location: Windsor, California
Posts: 843

On my plexiglas and lexan canopies, I generally use a small UniBit for the majority of the holes. Sometimes it results in a hole that is ever so slightly larger than the plans-specified hole -- but that is OK with me since the extra hole clearance provides slightly more room for the expansion/contraction of the plastic material. Another benefit of the UniBit is that you can very carefully use the next larger UniBit drill step to gently chamfer the edges of the hole. As noted above, practice on scrap material to build your confidence and perfect your technique. Also, be sure that the plastic material is warm!
David Heal - Windsor, CA (near Santa Rosa)
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Old 03-19-2018, 10:21 PM
caapt caapt is offline
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Location: Pottsboro TX
Posts: 81
Default Make sure the Temperature is warm enough

Plexi does not like to be drilled if it's too cool. Check me on this, but I think 65 degrees is considered a minimum. 85 is better.
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Old 03-19-2018, 10:31 PM
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flyboy1963 flyboy1963 is offline
Join Date: Oct 2008
Location: Lake Country, B.C. Canada
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Default make your own bits

if you take the drill size you want ( old and dull is ok) then use a Dremel with an abrasive disc.....put the bit in a vise, get out your reading glasses, and then take the 'rake' out of the bit.
grind the face of the cutting edge completely vertical, in line with the long axis of the bit. Some guys also point the bit like the fancy ones, but it's not entirely necessary.
You now have a milling tool.....much like the unibit.
It will SCRAPE it's way thru the acrylic, and won't 'grab' as you exit.

As other's have said, be sure you have a good, solid backup, and just go right into it so the hole in the acrylic is a nice cylinder.

smart to test, test, test before doing the real thing.
You'll know by the sound..... the rpm.... and pressure ....and speed of cut that makes nice curlies, and those that don't!
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Old 03-19-2018, 11:59 PM
Bavafa Bavafa is offline
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 3,069

Lots of good advise, none applies to my situation as I have already drilled it and honestly the chip is so small that can not be seen without a naked eye.

I have done the backing it with a piece of wood method when is possible, the canopy is backed by its frame and not possible to back it with a piece of wood. Also a uni-bit will not work with thick material unless you don't care about the size. If one is OK with going to a slightly larger size hole, I highly recommend a Plasdrill, you can get it at skygeek or Tap plastic. It works very nicely.
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Old 03-20-2018, 06:10 AM
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mike newall mike newall is offline
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Old 03-20-2018, 07:23 AM
BillL BillL is offline
Join Date: Sep 2007
Location: Central IL
Posts: 5,170

Originally Posted by caapt View Post
Plexi does not like to be drilled if it's too cool. Check me on this, but I think 65 degrees is considered a minimum. 85 is better.
They don't like hot either, so, when drilling many holes, the bit gets hot. Just dipping the bit in a cup of water before drilling provides enough lubrication and cooling to make a much cleaner hole. I discovered this when drilling dozens in plexiglass for a different project. It made a significant difference.

BTW - I use the Avery bits that look more like these.


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Old 03-20-2018, 07:07 PM
Stockmanreef Stockmanreef is offline
Join Date: Nov 2012
Location: Midland, mi
Posts: 786

I plan to buy permagrit 100 degree counter sinkers to counter sink. They might be able to clean up the hole edge if used carefully.

Go to this site for drill bits of all numbered sizes for plastic. I just bought some.

Just a thought, since I have not yet done this step.

I emailed vans about scrap plexiglass. I got an call from the canopy manufacturer and 3 days later I have scrap plexiglass. I just had to pay shipping.

good luck.
Ken Stockman
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