| What is the best bit to mortise stiles-rails that receive panels? I
| recently used an up-cut solid carbide and noticed 'minor' chip-out
| at the top of the mortise.
| Ordinary straight bit? Down-cut spiral?
A down spiral will have the least tendency to raise wood fibers at the
top of a mortise, but will also tend to pack the chips into the bottom
of the mortise.
Chip-out in a mortise may be a sign of a not-so-sharp (even if
brand-new!) bit. A good, sharp bit should shear wood fibers rather
than breaking them.
If chip removal isn't a problem, then an ordinary (plunge cutting)
straight bit should produce the most consistantly good results.
DeSoto, Iowa USA