Odd pin block

[Ron Nossaman]

> When I double drill, since accuracy is the point,
> it's hard to center the second pass on the first hole unless 
> I switch bits before moving on to the next hole...a real pain.
> 
> I assume you don't change bits for each hole, right?  If you come back to all the 
> 1/4" holes for the second pass,how do you spot the center.
> 
> Jim I


All the 1/4" holes first, then all the 6.8mm. Just one bit 
change between passes. It has always been my impression that 
it would be difficult not to center the second pass. I drill 
in the piano, with my hovercraft drill press setup, and the 
second pass seems to center pretty much automatically with a 
regular jobber bit. Maybe there's a potential problem I'm not 
aware of here. What sort of drilling rig and procedure do you use?
Ron N