KEEPING IT ON CENTER

KEEPING IT ON CENTER

Sometimes, we get those cores in the shop where someone had previously attempted to drill out a broken fastener, and they wander way off-center. We often need to install a larger repair insert than we normally would. I like to use a piloted counterbore cutter to drill...
TAP DRILL SIZES

TAP DRILL SIZES

When you need to make a thread repair, and someone has “borrowed” your tap drill size chart, here is a little trick. Subtracting the pitch from the nominal thread O.D. will get you very close to the tap drill size for a 75% thread. Here are some examples:...