I ran across this question in another forum: How do you choose between a countersink or a counterbore for a machine screw? Is there more to it than looks?

I think the original question should have said "counterbore" instead of "countersink" since he clearly referenced socket head cap screws in the title.

Also, the OD of the countersink tool should match the head of the flush SHCS. In order to seat the screw truly flush the countersink is intended to slightly counterbore the hole. If you use a countersink that is …

Nov 2, 2009 · You won't break any speed records, but you also shouldn't run into some nasty chatter problems that you can get with a straight multi flute countersink, (quick way to trash out a carbide …

Mar 10, 2013 · I have a 6-flute countersink I love for big screws, but it doesn't get used all that much. The great thing about being in the US is that an 82-degree countersink works for both 82-degree and …

Jan 3, 2011 · Counterbore use - First you drill the body drill sized hole for the screw you are using - that should match the size of the pilot on the end of the counterbore. Then you feed the counterbore the …

I use 1/32" over only. Drill the hole, then stick the pilot in the hole run your counterbore around 1/3 to 1/2 the the drilling speed. To properly sink a CB you use the diameter of the screw plus the clearance, in …

Aug 12, 2011 · 7/8" or 1" Forstner first, to the depth of the flange, followed by 1/4" counterbore. The spurs from the flange will hold it in position.

Jul 3, 2023 · I find that the O-flute countersinks do a better job on such metals. I am not too certain that a countersink that is not concentric with the thread or hole is a real problem. But I can see how a …

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