I was drilling some aluminum today in the mill (g0704) and spotted all my holes with a #3 center drill. Drilled 10 at 3/8 and one at 1/2 inch. All through a piece of .600 inch stock. The half inch hole is .505 at the bottom and .520 at the top. All of the 3/8 holes were tapered as well. I did not run the bit much past the stock. Ran at 1500 rpm and had good ribbons coming off.
What went wrong? I don't recall ever having a hole come out tapered like this. Any advice to prevent this from happening. Yes I should ream to get an accurate hole but I was not expecting a taper. Also used a brand new set of hss bits. Any advice is welcome.
What went wrong? I don't recall ever having a hole come out tapered like this. Any advice to prevent this from happening. Yes I should ream to get an accurate hole but I was not expecting a taper. Also used a brand new set of hss bits. Any advice is welcome.