Cap screw counterbore

[chips&more]

Maybe try this:


http://www.msdiscount.com/columnar....erer=https://www.google.com/&sessioncookieset

 

[Andre]

I've found that if your spindle bearings are bad, counterboring using a non pilot tool causes the endmill to wobble some. A piloted counterbore bores truer.

If you go the endmill route, try a 3 flute endmill. Soooo much better then a 2 flute or 4 flute center cutting. (Odd number of cutting edges seem to help with vibrations an harmonics)