Description
Brass screws add class to any project, but putting them into hardwood can be a trial. If you drill the hole too large, you get poor grip. If you drill at exactly the root diameter, you risk torquing the head off.
Using machine screws in drilled and tapped holes is the answer as they resist pullout in hardwood much better than wood screws. In some applications, such as installing small hinges, they also prevent wood splitting. In our tests, we observed that wood screws, generally, are poor in thread engagement depths of 1/2" or less; machine screws are at least twice as strong in 1/4" and 1/2" holes.
We have designed sets where the tap drill size is at the thread root diameter and the clearance drill is just a touch larger than the thread crown. If you need to bind two pieces together, you drill the top one with the clearance drill to avoid bridging. When you tap, you get 100% of the thread holding. The system works well and gives you holding power that far exceeds regular brass wood screws.
The individual number sets listed below include a tap, a tap drill and a clearance drill to match. The tap handle is available separately. The master set includes the five sizes from #2 to #10, plus the 1/4 -20 set (invaluable in jig and fixture work around the shop), as well as a tap handle.
