Forstner-pattern bits are used
wherever edge-holding ability is needed, such as in the overlapping holes
of a mortise.
The razor rim allows the bit
to hold perfectly, even if the brad point is over a void. Since the rim
is several thousandths of an inch higher than the chippers, the bit enters
cleanly and the double chip channels clear well.
The bit gives a cleanly cut,
flat-bottomed hole ideal for plugging. A primary use for this bit in the
woodworking industry is to drill out knots for later plugging.
Saw tooth bits (usually over
1" in diameter) are primarily for use in a drill press. They are most
useful for boring smooth, clean holes in all wood varieties at any angle.
The double chip channels are less subject to rim heat than forstners and
are easier to sharpen. Although their edge-holding ability in overlapped
holes is slightly less than forstners, the difference is negligible in