LumberJocks

Driving a Drum Sander

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by captfoss posted 10-31-2012 03:09 PM 1688 views 0 times favorited 18 replies Add to Favorites Watch
View captfoss's profile

captfoss

20 posts in 968 days


10-31-2012 03:09 PM

I’ve seen various designs for drum sanders, either of the v or thickness variety, which are shop-build and call for belt-driven motors that range from as low as 1/4 HP all the way up to 1 HP, which I price anywhere from $60+ just for the motor.

Most of the designs I’ve seen seem to descend from this project:
http://www.rockslide.org/drum%20sander.html

Which uses a 1 HP motor to drive what appears to be a 3” diameter, 14” long drum.

I was wanting to get people’s opinion on doing a similar drum thickness sander, but driving the drum directly with a cheap drill from Harbor Freight. Specifically,
http://www.harborfreight.com/power-tools/drivers/1-2-half-inch-heavy-duty-variable-speed-reversible-drill-3273.html

It’s rated at 1080 watts, which if I’m doing my calculations correctly, means it’s a 1.4 HP motor with full-speed torque rated at ~6 foot pounds.

The math all adds up that the drill should have more power than the 1 HP motor used in the original project, but I assume I’m misunderstanding something about how motors work.

Advice would be great.


18 replies so far

View Bill White's profile (online now)

Bill White

3582 posts in 2708 days


#1 posted 10-31-2012 03:25 PM

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

-- bill@magraphics.us

View crank49's profile

crank49

3522 posts in 1719 days


#2 posted 10-31-2012 03:40 PM

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.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Swyftfeet's profile

Swyftfeet

169 posts in 919 days


#3 posted 10-31-2012 03:50 PM

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

-- Brian

View jap's profile

jap

1240 posts in 802 days


#4 posted 10-31-2012 03:54 PM

agrees^with all the above

-- Joel

View DIYaholic's profile

DIYaholic

14588 posts in 1423 days


#5 posted 10-31-2012 04:05 PM

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.

-- Randy-- I may not be good...but I am slow! If good things come to those who wait.... Why is procrastination a bad thing?

View captfoss's profile

captfoss

20 posts in 968 days


#6 posted 10-31-2012 04:10 PM

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?

View Gene Howe's profile

Gene Howe

6052 posts in 2177 days


#7 posted 10-31-2012 04:45 PM

”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.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View crank49's profile

crank49

3522 posts in 1719 days


#8 posted 10-31-2012 05:22 PM

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.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Swyftfeet's profile

Swyftfeet

169 posts in 919 days


#9 posted 10-31-2012 05:40 PM

and double the torque!

-- Brian

View dbhost's profile

dbhost

5387 posts in 1980 days


#10 posted 10-31-2012 05:45 PM

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.

-- My workshop blog can be found at http://daves-workshop.blogspot.com

View Loren's profile

Loren

7822 posts in 2396 days


#11 posted 10-31-2012 06:05 PM

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.

-- http://lawoodworking.com

View captfoss's profile

captfoss

20 posts in 968 days


#12 posted 10-31-2012 07:07 PM

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?

View Loren's profile

Loren

7822 posts in 2396 days


#13 posted 10-31-2012 07:12 PM

You’ll smoke the router.

-- http://lawoodworking.com

View captfoss's profile

captfoss

20 posts in 968 days


#14 posted 10-31-2012 07:26 PM

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

View HalDougherty's profile

HalDougherty

1820 posts in 1985 days


#15 posted 10-31-2012 07:42 PM

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.

-- Hal, Tennessee http://www.first285.com

showing 1 through 15 of 18 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com

Latest Projects | Latest Blog Entries | Latest Forum Topics

GardenTenders.com :: gardening showcase