A POX ON IT!
Seriously, I have no idea what I'm doing wrong here, but this thing is acting like the mill isn't squared, when it is in fact squared to the best of my abilities. Both "roll" and "pitch" of the Z-axis assembly (I'm using a Sherline model 2000 mill) square up just fine with respect to the table. However, the fly cutter always seems tilted. If I take 5 mils off of a piece of aluminum when the bit hits the metal in the initial 180 degrees, it's likely to take off nearly 20 mils when it hits the metal coming around the next 180 degrees. I'm fairly sure the work isn't moving around, and I've tried to square the milla s best I can. The bit has been used on aluminum and some cast iron.
The Sherline book makes a note about this behavior in fly cutters, but this is beyond what I would expect. Can anyone tell me the most likely sources of error? It seems I'm either not squaring the mill correctly, using a dull bit (I don't think it should be dull by this time... it is carbide), or there's some fly cutter technique that I'm missing.
Any ideas?
Thanks.  |