05-01-2020, 01:59 PM
I use these types of counterbores I get from McMaster.
https://www.mcmaster.com/counterbores/me...nterbores/
I buy them as I need them. I think I have them for #4-10 screws, 1/4" & 5/16" and maybe a metric one or two. Going from memory so might not be accurate.
They are pricey but once you've used one you'll want more.
Ed
EDIT: Oops! These won't work for threaded holes. The pilot size is larger than the bolt size.
https://www.mcmaster.com/counterbores/me...nterbores/
I buy them as I need them. I think I have them for #4-10 screws, 1/4" & 5/16" and maybe a metric one or two. Going from memory so might not be accurate.
They are pricey but once you've used one you'll want more.
Ed
EDIT: Oops! These won't work for threaded holes. The pilot size is larger than the bolt size.