Counterbores - what are you using?

[Highpower]

(05-01-2020, 04:48 PM)TomG Wrote: I can't think of very many reasons to counter-bore a threaded hole. Counter-bores are mostly used to sink the head on through screws, normally socket head cap screws. I have a four flute set that is 1/64" under, with nominal size pilots, for screws up to 1/2" diameter. That's pretty much all I use. For anything larger than 1/2", I would bump the size up to 1/32" over.

Tom

Yes I think that is where I was getting things confused. The descriptions for these things are non-existent. They say things like "before thread" 1/64" over or 1/32" over (FINE AND MEDIUM???) whaaaaa???  

I thought they were talking about pilot sizes but apparently they mean the OD size of the cutter?
I went and ordered the only metric set that McMaster sells so I'll get what I get I suppose. Then a couple hours later I saw a good deal on an imperial set on Amazon so I bought that too. My imperial step drills that I been using never seem to have the right pilot size and/or the right diameter to closely match the diameter of a socket head screw. Especially metric ones!  

Hopefully having the right cutters will make things easier in the future.