Drilling holes in A&C body with gel coat

1BIG67AC · #1 (**permalink**) 07-20-2019, 10:50 AM

Guys this is my first post on this forum and I need a-little help. My butt pucker emotion is ready to go up!

LOL! I’m in the process of drilling out and installing the hood and trunk handles onto the body. It’s saying in the instruction to use a 3/4 hole saw to make the holes. Is there any specific type of hole saw? High speed, what tooth count and any particular brand. I was told that a wood Forstner Bit would work. I’m just nervous about drilling into the gel coat of the body and chipping it out. Anyway your help would be appreciated thanks.

saltshaker · #2 (**permalink**) 07-20-2019, 12:25 PM

I put blue tape on the body and drilled thru that.
Jon

1795 · #3 (**permalink**) 07-20-2019, 12:31 PM

I would suggest using the highest teeth count that you can find. In addition put painters tape over the area to be drilled and then once the center bit in the hole saw and the teeth have made contact, remove the saw, go to the underside, tape that area and then line up the center drill bit with the hole and drill just deep enough from the back side to cut into the fiberglass to prevent blowout on the back side. Now go back to the topside and continue driving through. This should make as clean a hole as possible and prevent the backside of the hole from blowing out as the bit goes through.

Good luck. Every time i drill hole in something nice, my butt puckers a little too.

Jim

spdbrake · #4 (**permalink**) 07-20-2019, 01:41 PM

Uni-bits are safe for Fiberglass, Composites, Plastics and and can't be beat for Plexiglas. No blowout, chipping or crazing.

The only real drawback can be the thickness of the material. In your case though a #3 Bit PN 10233 (max dia is 3/4") should do a great job.

Also Uni-bits can be laterally "walked" if you see you off a bit on center line.

https://www.irwin.com/uploads/produc...etal_eBook.pdf
https://www.irwin.com/tools/drill-bi...tep-drill-sets

If you do decide to use a hole saw. Once the pilot tip is thru run the drill in reverse while you cut thru the Gel-coat to help eliminate chipping. Then switch back to normal R/H drilling rotation. As others have said, its good idea to go to backside and score the hole with the the bit to prevent a lot of final hole blowout chipping.

1BIG67AC · #5 (**permalink**) 07-20-2019, 07:47 PM

Gents thanks for the info. Now it’s time to man up and just do it! I’ll let you guys now how it comes out. I’ll keep my finger crossed too!

H-Rod · #6 (**permalink**) 07-22-2019, 08:49 AM

Quote:

Originally Posted by spdbrake

If you do decide to use a hole saw. Once the pilot tip is thru run the drill in reverse while you cut thru the Gel-coat to help eliminate chipping. Then switch back to normal R/H drilling rotation. As others have said, its good idea to go to backside and score the hole with the the bit to prevent a lot of final hole blowout chipping.

All the round holes I drilled in my car were with a holesaw spun in reverse.
Drill your pilot hole (in reverse) then use that as a guide for the drill in the hole saw.
I also laid down some painters tape while I did this.
No chipping, cracking or anything.

If you think drilling for the hood latches is a booger, wait til you drill for the roll bar.

cycleguy55 · #7 (**permalink**) 07-22-2019, 10:51 AM

Quote:

Originally Posted by H-Rod

All the round holes I drilled in my car were with a holesaw spun in reverse.
Drill your pilot hole (in reverse) then use that as a guide for the drill in the hole saw.
I also laid down some painters tape while I did this.
No chipping, cracking or anything.

If you think drilling for the hood latches is a booger, wait til you drill for the roll bar.

Reverse is okay for high speed steel hole saws, but not for carbide-tipped - they may survive that in fiberglass, but the carbide tips are designed and attached only for conventional drilling and could be ripped off if run in reverse.

Personally I wouldn't do it with carbide-tipped hole saws. Just my 2¢.

saltshaker · #8 (**permalink**) 07-22-2019, 04:04 PM

I’ve built a couple A&C’s... spade bit for the windshield wipes and hole saw for the rest from harbor freight. Tape the body, drill the pilot hole and reverse the hole saw to start it then go froward. I never chipped the body on any builds.
Jon

Jaydee · #9 (**permalink**) 07-22-2019, 05:40 PM

I haven't tried it, but would a stepped drill work?
JD

PNJSNAK · #10 (**permalink**) 07-22-2019, 07:07 PM

Blue painters tape and hole saw in a variable speed drill.
Take your time and go slow, let the drill bit and the Hole saw do the work.
For cuts in body for windshield frame and side pipes I used an air operated small reciprocating saw.
If you think it’s pucker time for the hood and tail gate wait until you do the front jack support tube holes and the side pipe cutouts. On the front jack support tube holes just go straight in and let the edge of the hole saw bit in, take your time.
Good luck,
Jim

1BIG67AC · #11 (**permalink**) 07-22-2019, 11:31 PM

Well I went ahead and ordered the step bits and also bought a new 3/4 hole saw with the highest count teeth I could find. I know that the holes that came in the body when I received it from A&C are perfect. I also emailed Ron at A&C to see what they used but he has not returned my email yet. I’ll let all of you know my out come. Keeping my fingers crossed.