I've been using brand new Norseman stub length bits, drilling through 1/8 and 3/16 1080. I used a new 3/16 bit and drilled 11 holes and still had a little more left on the bit. I used two new 1/4" bits and only got two holes each. Running at my press' slowest speed, 620 RPM. What am I missing? Why the heck can't I get the 1/4 holes to work?