What size countersink for m3 holes?

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LicketySplit

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I have to drill holes in my scorched CF chassis for battery strap holders. Google has me leaning towards 1/2" 90 degree 6 flute since it's a metric screw. Am I wrong? Would 3/8" be better? Also, links would be appreciated. I know @LibertyMKiii works with CF so maybe he knows.
 
M3 screws are pretty tiny. A 3/8” dia countersink will likely be more manageable because the flutes should be finer at the tip than the 1/2”. Just as long as its 90° It should work. Carbon fiber is kind of a pig to work with because it likes to splinter rather than make a chip when cut.

Side note American fasteners have a 82° included angle.
 
Scorched sells drill bits and a countersink for his chassis’. Email David and ask him what size countersink he uses.

https://scorchedparts.co.uk/products/carbon-fibre-drill-and-countersink-kit
I saw those. Already emailed them. His response was that they had no idea when they get back in stock. That’s it.
M3 screws are pretty tiny. A 3/8” dia countersink will likely be more manageable because the flutes should be finer at the tip than the 1/2”. Just as long as its 90° It should work. Carbon fiber is kind of a pig to work with because it likes to splinter rather than make a chip when cut.

Side note American fasteners have a 82° included angle.
That’s kinda what I was thinking. Figured 3/8 would be easier. I’ve drilled CF before and just went slow on a drill press with wood backing. No issues.
 
I saw those. Already emailed them. His response was that they had no idea when they get back in stock. That’s it.

That’s kinda what I was thinking. Figured 3/8 would be easier. I’ve drilled CF before and just went slow on a drill press with wood backing. No issues.
I use a ryobi counter sink bit, but I am not sure if it is really the correct angle/size for M3 screws. I was typically countersinking for M4 size.

Maybe this one which is the smaller size than what I use?

https://www.homedepot.com/p/RYOBI-5-8-in-High-Speed-Steel-Countersink-A10CS82/205469295
 
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