: Jeff,
: I have a lead now on an old forced air furnace that I can have the
: motor if I want. Not sure what hp that would be but I would like
: to look at it, besides it's 200 miles away.
: Thanks!

Bill-
I probably wouldn't drive 400 miles to get a furnace motor, but:
If it is an oil-fired furnace there are probably two motors available- the circulating fan motor, and also the air blower motor bolted to the side of the burner assembly. I made a spindle/drum sander with a blower motor which lasted quite a few years. Low HP , but did the job. The blower motors are also sealed units, so fairly dust resistant. You'd need to fix a bracket to mount the blower motor horizontally.
Some circulating fan motors are very 'open' so perhaps some sort of dust protection would be a good idea.

More HP is always handy (my 12 disc sander has a 1 (Chinese) HP motor), but you can get by with what you can find for that sander. If you are not using the belt, (I don't know if it slips off easily on that model) removing it can reduce the power requirements a lot. Also, using sharp sandpaper on the disc requires less power- the bigger motor comes in handy on the 'just one more job and I'll change the disc' days.... There's not much startup torque on a sander, so most any old motor will do.

It's fun getting old tools running again....but it was a lot easier when they let us visit the dump aka handyman shopping mall!
;-)