I got some cast iron from Metal Express and milled a small cube, about an inch in each dimension. Then I tried to drill a 1/8 inch hole through it. Just as the bit was emerging, it broke. So I tried it again, this time with lubrication, and the same thing happened. I do not understand this. The cast iron is soft and easily drilled.
What is causing this, and what can I do about it?
Thanks,
Will