On a final note for tonight, there has been some confusion on this thread as to how angles are measured in champhers, counterbores or countersinks. In every country that I know of, the angle of a countersink in a hole is measured by the total angle the cutter makes in the hole. In other words, you take a protractor and measure the angle the cutter makes on BOTH sides of the flutes. (Pictures will help...tomorrow).
Champers, on the other hand, are defined by 1/2 of the total angle. Therefore, a 45 degree champher makes a 90 degree countersunk hole. Champers are defined by degrees because you can make a 45 degree champer on the edge of a rectangular part--the other side of which can be on the other side of the casting, or not even there at all. On a hole, however, they measure both sides.
I know it can be confusing. I added a link to a countersink supplier. Notice the industrial standards (that are used all over the world, by the way).
60, 82, 90, 100, 120 degrees...76 degrees is not used anywhere I can find.
http://www1.mscdirect.com/CGI/NNPDFF...0&PMT4TP=*LTIP
David
