I would like to drill holes for socket-head cap screws to permit the head of the screw to be recessed so that it is flush with the surface of the material that I am drilling.
I believe that one tool designed for making such holes is a counterbore bit.
For example, I'm considering getting the set of HSS counterbore bits shown at http://cgi.ebay.com/7-PCS-HSS-COUNTE...#ht_1662wt_802
Although I have a general idea of their proper function, I'm not completely certain how to use them.
Do I drill a through clearance hole in one operation and then use the counterbore bit in a second drilling operation, using the small "pilot" end of the bit to center the bit before plunging in with the 3-flute drilling/reaming portion of the bit?
I believe that I have seen counterbore bits that have cutting edges for the pilot section as well as for the socket-head-cutting section. The photo in the eBay listing link above is a little unclear - are the edges of the pilot section used in those bits smoothly-ground or do they have cutting edges?
Is there an alternative to using these bits to do counterboring for socket-head cap screws? For example, do they make reamers with pilots, or are these bits essentially just reamers with pilots?
These will work well in 6061-T6 aluminum, right? Guidance on what rpm to use with these bits in aluminum would be appreciated. Do I need to use a cutting fluid or can I get away with using them dry? Are these things foolproof, or are there tricks of the trade that will prevent me from messing things up?
I haven't ever used a reamer before (other than one of those hand-held pointy things). I suppose that the answers to my questions are buried somewhere in my Machinery's Handbook, but I'm lazy, sorry...
The smallest bit in this set is for a #6 screw. I'd like to find a counterbore bit for a #4 screw and also for a #2 if possible - any pointers would be appreciated (my search capabilities seem to be failing me).
That's probably enough questions for now, thanks...