If you look at the information you quoted ( Porter-Cable) the grinders are
rated at one speed. Also if you can lean on a 7 amp grinder enough to slow
it down, you have produced enough friction to have already burned through
the gelcoat. Again if 3M recomends a max of 3000 rpm, and you exceed with
sucess I commend you, you were lucky, and very careful. Besides B&D shows
only 2 grinders on their site, both 4 1/2" dia with a speed of 10,000rpm
http://www.blackanddecker.com/produc...owertools.aspx nothing with a
variable speed though. They do show a polisher on that site. Again I have
used many hand held or Snag grinders, none with variable speed, though they
may exist. I work on boats a little more than once a year by the way.
"Bobsprit" wrote in message
...
Bob, I am a tinsmith and use these tools every day. A grinder has the
lowest
speeds you state, and are way to fast for polishing, They also use a much
higher amperage draw than a polisher and will not slow as a polisher will
with pressure. They do not have a variable speed range and will burn
through any gell coat at their rated speeds, read the can a can of
compound
from any reputible manufacturer such as 3M or Norton.

Yes, indeed, you ARE busted. My B&D Grinder and several other's I've seen
ARE
VARIABLE. Some DO have variable speed. One of the Porter Cable units I
used to
use was also variable. Mine goes down to 2500 RPM, though I use higher RPM
during jobs.

http://www.powertoolservices.com/too...on/6154-70.htm

Meanwhile 3M suggests a max RPM of 3000 RPM, but you can safely exceed
that by
a good margin. We certainly haven't damaged any hulls using the B&D.
Meanwhile
I've never used ANY grinder that didn't slow down quite a bit with a big
polish
pad on it and under load.
Stop talking about stuff you don't know about. I actually work on boats
every
year.

RB