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How big a hole?

74 Bronco Billy

Contributor
Sr. Member
Joined
Jul 4, 2016
Messages
775
I am epoxy powder coating my '74 tub and it has War Flares from WH on it. I plan to use 10-32 Button allen bolts to attach. A 10-32 bolt fits easily in a 3/16 hole, so, how much bigger do I need to drill the hole to account for the epoxy powder coat, the body primer, color, and clear coats so that I will not have to drill the hole out again when the paint job is done?
Should I account for 1/64, 1/32, 1/16, or 1/8 inch of powder and paint thickness overall?
I can drop down to a 8-32 bolt, it fits a 11/64 hole, but the head is a lot smaller than the self tapping screws that came with the War Flares, so then I might need to go to a washer....not a very good look. So, back to the 10-32 bolt, and how much thickness for powder and paint should I account for?
3/16 + 1/64 = 13/64 hole
3/16 + 1/32 = 7/32 hole
3/16 + 3/64 = 15/64 hole
3/16 + 1/16 + 1/4 " hole Yikes?
Thoughts anyone?
Thanks , Forrest:D?
 

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Nevadasmith

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Apr 30, 2016
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Fallon, Nv
I worked at a place that did powder coating for a while, I wasn't a part of that process, but they used little silicone plugs in all the holes to keep from re drilling and or tapping.....that way even if the powder got applied to thick the hole was still good, different powders seem to go on with different thickness....so I don't think you will get a solid answer to the question you are asking.... But if you do go slightly to large, you could always use a 10-32 flange nut..... Good luck
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,821
I would ask the powder coater how thick the material lays down?
Next think that screw threads are like a (poor) saw blade. even if the hole is large enough sliding them in or even spinning them around as you screw them into the nut on the backside.

If you are wondering what size hole to drill to the 64th, you are probably over thinking it. Guilty many times. I would probably be grabbing the bit just under ¼" as it will be large enough and probably sharper since I don't normally use it.
 
Joined
Feb 10, 2007
Messages
34
I would probably go with 7/32. Not to big if there is no build up in the hole but if it's a little tight you can use a round needle file or small chainsaw chain file to open them up if some are to small after powder coat. The fine file shouldn't chip the powder coat too easy. Just my 2 cents.

Sent from my Pixel XL using Tapatalk
 
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74 Bronco Billy

74 Bronco Billy

Contributor
Sr. Member
Joined
Jul 4, 2016
Messages
775
I worked at a place that did powder coating for a while, I wasn't a part of that process, but they used little silicone plugs in all the holes to keep from re drilling and or tapping.....that way even if the powder got applied to thick the hole was still good, different powders seem to go on with different thickness....so I don't think you will get a solid answer to the question you are asking.... But if you do go slightly to large, you could always use a 10-32 flange nut..... Good luck

Thanks, they use the silicone plugs, but not for real small holes, mainly threaded ones

I would ask the powder coater how thick the material lays down?
Next think that screw threads are like a (poor) saw blade. even if the hole is large enough sliding them in or even spinning them around as you screw them into the nut on the backside.

If you are wondering what size hole to drill to the 64th, you are probably over thinking it. Guilty many times. I would probably be grabbing the bit just under ¼" as it will be large enough and probably sharper since I don't normally use it.

I know I am way over thinking it, but I'm trying to not have rust in the future ;D;D;D

I would probably go with 7/32. Not to big if there is no build up in the hole but if it's a little tight you can use a round needle file or small chainsaw chain file to open them up if some are to small after powder coat. The fine file shouldn't chip the powder coat too easy. Just my 2 cents.

Sent from my Pixel XL using Tapatalk

I like your idea of the chain saw file, makes perfect sense, real fine too. Thanks a lot.

Forrest
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
I used 3/16 drill and ran them through to the round part of the shank of the drill to ensure a round hole.

You would need to go larger to have any powder coat covering the edge of the hole.

I used Blackened stainless steel button heads and washers from Mc Master Carr and the black surface has held up for over 5 years now even when polishing the flairs by hand to keep them shiny. And yes you can polish the War Flairs. They are solid color throughout.
 
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74 Bronco Billy

74 Bronco Billy

Contributor
Sr. Member
Joined
Jul 4, 2016
Messages
775
I used 3/16 drill and ran them through to the round part of the shank of the drill to ensure a round hole.

You would need to go larger to have any powder coat covering the edge of the hole.

I used Blackened stainless steel button heads and washers from Mc Master Carr and the black surface has held up for over 5 years now even when polishing the flairs by hand to keep them shiny. And yes you can polish the War Flairs. They are solid color throughout.

Thx for the idea. I did not know you could shine them back up. If you get scrapes in the flares, what have you used to polish them up?

Thx,
Forrest
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
For me sun fades them over time and they loose their shine so I use a mothers clay bar kit over them and them and 3m finesse after that.
 
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