The drill HP ratings are established at full speed, no load, just before the motor explodes. The drill is not designed for continuous duty either.
I wouldn't bother tryin' to use a drill to power a drum sander. (But what do I know?)
Bill

 

That HF tool is typical of their offerings. Either they do not know what the ratings are or they intentionally mislead you.
The specs in the HF link say 6.3 amps, 120 volts, 1080 watts. One of these numbers has to be incorrect.

Amps X Volts = Watts

6.3A X 120V = 756W

OR

1080W / 120V = 9A

On the other hand, in terms of driving the drum with a drill; I wouldn't do it.
The drill is a universal or series wound motor with brushes and sleeve bearings and a gear reducer.
It would not last very long running continuously. It's designed for intermittent use.
And the gear will be noisy and rob power through efficiency issues and waste heat generation.

A better choice for a cheap motor is a re-purposed bench grinder.

 

What Bill said. Those figures on the box or in the add are specific ideal points in time(for the rating) that hardly demonstrate actual use conditions. You would thermally overload a drill in very little time( a span of seconds) with a consistent full load like that.

Link

 

agrees^with all the above

 

There is no reason to pay full retail price for a motor, you can find a used motor in a free washing machine, or anything cheap on CL.

 

Ok then.

All of the bench grinders (6/5/3") on their site are rated at 3450 rpm, and commercial drum sanders are rated at approximately half of that. Is there a cheap solution to that problem?

 

"All of the bench grinders (6/5/3") on their site are rated at 3450 rpm, and commercial drum sanders are rated at approximately half of that. Is there a cheap solution to that problem?"

Pulleys, but someone else will need to provide info on sizes and ratios.

 

Look for a good old 8" or 10" grinder. Will usually be 3/4 hp or better. Might be 1800 RPM

If you need to reduce speed with pulleys, the speed difference will be the same as the pulley diameter ratio.

IE. 3400 RPM motor with 2" pulley driving a Drum with a 4" pulley. the Drum will be turning at 1700 RPM.

 

and double the torque!

 

Grab a dedicated proper motor. I see 1.5HP table saw type motors going cheap on CL pretty often.

I picked up a HF 1.5 HP motor. I have hooked it up to my drum, and as a temp test rig bolted it to a simply test jig, no adjustments, shoved 3/4" stock through it with no stalling, no burning. Took 1/8" off the stock no problem…

I am using a 24" wide drum.

 

For a drum thicknesser you want the strongest motor
you can get your hands on and run on the wiring you
have.

I recommend at least 1.5 hp.

 

What about driving it with a 1.5 HP variable-speed router set to the lowest setting (~10,000 rpms) and then further speed reduced 1:5 or so?

 

You'll smoke the router.

 

Ok, so how can you tell whether or not a particular motor is designed to be run for extended periods of time under load?

 

I bought a cheep lathe from someone on Craig's List and I use it as the base for my Drum Sander. I made two plugs to fit into the ends of a 3" piece of PVC. Then I made MDF circles that fill the tube. There's a 1/2 inch threaded rod in the center and the MDF circles are glued together. There isn't any flex and I made it to give me 12" of sanding area. Hose clamps hold the strip of sandpaper to the tube and two pieces of MDF hinged together with a threaded rod of elevation adjustment make up the rest of the sander.

Shipwright made a much better version using his Shopsmith for the base. Mine works just like it, but mine looks like it was cobbled together by a couple of blind monkeys compared to his.

 

Most any induction (capacitor start) motor rated for
"continuous" use should be suitable. You may want
to look for a "TEFC" which means "totally enclosed
fan cooled" for a sander, since the fine dust can
shorten the life of a non-enclosed motor.

Such TEFC motors are common too, being used,
among other things, for lifestock barn ventilation
fans where there is a lot of airborne dirt.

But in any case any used 110 volt AC motor you
can find over 1 hp and under $50 should serve
to get you started.

 

The correct motor would be an induction motor. rated for continous duty, closed vs open would be better, thermally protected would be ideal but$$$.

http://www.grizzly.com/products/Motor-1-1-2-HP-Single-Phase-1725-RPM-TEFC-110V-220V/G2534

would work fine a 1HP would be cheaper

 

Loren beat me to it. I just think you'll have to hunt CL to find one for $50