For reasons I can't understand, I seem to have a hard time getting deep drilled holes to go anywhere near straight. If I drill a hole, of almost any size, 1" deep, even through aluminum, the bottom will be significantly offset, in a seemingly random direction, from the top. The machine is well trammed, and I'm using quality, name-brand drills, and peck-drilling.

When I need both ends of a hole to be properly positioned, I'll drill half-way through one side, then re-drill the full depth from the other side, but this should not be necessary....

Regards,
Ray L.