"Leo Lichtman" wrote in message
...

wrote: (clip) they have reverse for turning and
sanding, always made for a better finish over here !!, (just like the
other Leo said).
^^^^^^^^^^^^^^
Good point about reverse for turning. Sometimes using reverse makes it a
lot easier to work inside a reentrant shoulder near the opening.

Regarding sanding in reverse, I once asked my son's shop teacher what he
thought, and he said, "Just turn the sandpaper around." ;-)

Well, Leos, the business of reversing directions comes from sanding flat
boards along the grain. Where the grain was rising along the direction of
sanding, the fibers could be laterally compressed into the spaces between,
which is why SOP was to make a water set and quickly sand in the opposite
direction. To remove those whiskers which might stand up later when
finishing, especially with shellac. Didn't make anything smoother. Grit
being grit, couldn't.


Since the grain meets the paper in opposite directions at either side of the
endgrain on a rotating bowl, this technique is not applicable even with hand
sanding. Also, as with flat work, where we now use orbital sanders, the
action of a rotary (power) sander actually cannot sand either with nor
against the grain, rotary in rotation, after all. It sands mostly along
with if we place the 3:00 or 9:00 o'clock portion of the disk in contact
with the rotating piece, differential speed (rotation of piece versus paper)
determining which direction the grit engages the grain. Sanding at 12:00
or 6:00 o'clock is especially efficacious at removing the ridging left by
gouges, or the semi-ridging (\ or /) left by finishing with the prior grit
at 3 or 9. Once again, makes no difference which way the piece is rotating.

Plain fact, easily observed.