Router Speed Control Meets 4X36 Stationary Belt Sander

[LowGear]

I thought it would be so easy.  Slow my cheapski stationary belt sander with a router speed control device so I can sharpen knives and the like.  You guys that known the outcome should shed the light upon my wrinkled brow.  As I looked at this https://smile.amazon.com/Work-Sharp-Sharpening-Repeatable-Consistent/dp/B003IT5F14/ref=sr_1_1?ie=UTF8&qid=1517709121&sr=8-1&keywords=knife+sharpener+belt+driven I knew I already had the stuff I needed or I thought I did.  So how do I slow it down and why didn't my brainstorm work?

[mobile_bob]

my bet is your stationary belt sander is powered by an induction motor... as such a speed controller will not work!

the induction motor must have 120vac nominal at 60hz (US)

routers use brush type universal motors, they can run on just about any hz, and some even DC power
the router speed controller simply alters the voltage delivered to the brush type motor to vary the speed of the router
(simply put), there are pwm units that chop the power up and maintain rpm via some form of feedback.

anyway that is my bet as to why your scheme didn't work as you would have liked.

bob g

[mobile_bob]

your title line states you have a 4x36 belt sander?
the amazon linked unit looks like a 1" belt?

which do you have?

every 4x36 belt sander i have seen is powered by the induction motor i alluded to earlier

the 1" job, might well work with a router speed controller.

bob g

[LowGear]

Sorry mobil bob.  The Amazon link shows the tool I want to transform my 4 X 36 belt sander to.  Out of the box it runs too fast and burns everything I try to sharpen except maybe for the spade and concrete scraper (re-purposed to whacking banana plants at 10 feet so the fruit doesn't fall so far).  Even my "big boy" machete gets scorched now and then.

A neighbor has one of the Amazon units and his machete cuts like a proper boning knife.  I can get 300 grit belts that should really snap my edges up to near surgery standards.  glort linked me to some SRC devices that should work if they weren't set up to work at 220 with Australian plugs but I know it's a five minute search on eBay once I get the proper terms in the search query.

[mike90045]

What was the secret fix ?

[LowGear]

The fix was using a brushed motor like on my handheld belt sander with the router speed control.  I still don't get the edge that the dedicated sharpener gets but I haven't tried the 150 grit or finer as does the one on Amazon.  The slower speed gives me time to move the blade around and to watch more closely for hot spots.