dadiOH wrote:
"Bill" wrote in message

"Stupid" disk sander question (this thread seems like a good place for
it).
Are there wood sanding applications where a smaller, less powerful disk
sander works better than a larger more powerful one?

For instance, 9" 3/4-HP, versus 12" 1 HP.

I know sandpaper would be cheaper for the smaller one, but that's not
what I'm talking about. Clearly the larger disk gives you more working
room, but is there a downside to it (besides the higher cost per sheet
of abrasives)?

Well, the outside three inches will be moving farther in a given time
but I don't know if that is a benefit or vice versa.

Most disk sanders seem to be about 3500 rpm; at that speed, it is easy
to burn wood, need to have a light touch which is easy enough to do.
Still, I'd rather have one that is doing 1750 rpm; trouble is, they
charge more for them, no idea why.

All of the 12" ones I saw said 1725-1750 RPM, except Jet didn't
list the RPM (I would expect the same).
The 9" one I was looking at (part of a belt/disk combo unit) said 3100
RPM. Interesting.
The circumference of a disk is directly proportion to the diameter.
12*1750 =21000 (*3.14) feet per minute, at the edge.
9*3100 = 27900 (*3.14) feet per minute at the edge, so these numbers are
NOT different by factor of 2, like it appears at first glance.
More like 25% difference. And the 1 HP number probably has more integrity.

Thanks for making me think!
Bill




Somewhere in this thread - I think it was this thread, I've sorta lost
track - someone mentioned the nuisance factor of changing grit on a
disk sander. True. The solution is, put on an 80 grit disk and never
change it until it is worn out then stick on a new 80 grit, on top of
the old one or on the plate, your choice.