Still more tips for a manual mill

Continuing and concluding the theme of my previous two columns, this month’s installment provides additional tips for enhancing the operation of a manual milling machine.

• For working on large plates, make a couple of spreader bars. The spreader bars have counterbored bolt holes on the same centers as the T-slots. Make the spreader bars out of something relatively soft so they can be sacrificial.

• Rounding the corners of a standard drill bit with a honing stone enables the drill to impart a finer hole finish. This is a sneaky way to get around not having an odd reamer size. You can also manually grind a twist drill a bit off-center to have it cut a whisker larger.

All images courtesy T. Lipton

Use a honing stone to round corners on a drill to impart a finer hole finish when you don’t have an odd-size reamer.

A slip of paper can be used to measure and indicate the back clearance, or relief, angle on a drill bit.

A cutoff piece or O-ring cord stock provides the right amount of squeeze and friction to securely hold multiple parts.

You can use a drill chuck as a hand tapping guide if you leave the collet loose.