Slack Belt Grinder - Unplugged

C

cliff355

Joined
Apr 19, 2003
Messages
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Recently I slapped this device together from stuff I had lying around the garage. It holds a 1" x 42" belt like a bowsaw blade, and tension on the belt can be adjusted with the red-handled lever device (one of those woodworking jig-related things from Rockler Hardware). The lever device also releases tension immediately, allowing for quick belt changes.

In use, you can either put the blade in a vice and run the belt over it, or hold the tool in your lap and pass the blade back and forth like a strop. When the blade is in a vice, it works best if the two vertical "legs" are gripped as handles. This, along with the adjustable tension allows a very precise amount of convex edge bevel to be placed on a blade. In addition, you can see exactly what progress you are making and tailor each pass of the belt accordingly.

All my khuks are paper-slashing sharp at the moment, so I tested the tool out with a 220-grit belt on a Ontario Machete blade. Frankly, I think it may work better than my motorized belt grinder. The 220-belt removes metal fast, but not so fast that you can make a little mistake and screw the whole thing up. Also, the blade doesn't get hot.

So, if you don't have the space or money for an electric grinder, you can make one of these for about $10 - and you won't have to wear a dust mask using it either.

Maybe at some point I will get some 2" x 72" belts and make a 2-man crosscut version. Anyway, many thanks to the wife who allowed me to postpone putting up Christmas lights until I was done tinkering with this.
 

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Here is a closeup of the lever device from Rockler Hardware (Woodcraft has them too, probably Lee Valley also). I don't think the rubber tip is going to last, so eventually I'll probably screw a metal plate on the leg and let the bolt bear directly on it.
 

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I've envisioned something along those lines, but your setup blows my idea out of the water! I may just build one of those next week. Thanks a million man.
 
Most excellent! Great idea, and nice work.

Bruise, post your address and we'll send the wood.;)

Steve
 
Nice setup! Can you post the specs on it? That way I don't have to do any experiments when I build mine. I think I have something similar for the tensioner. I would have never thought of something like this, myself.
 
Regarding the measurements, the cross piece is 20" x 4" x 2" thick, and the two "legs" are 12" x 2 1/4" x 1" thick. All boards were #2 pine, and planed to 1" for some reason (can't remember - they were at the bottom of the scrap bin). The sawed-off U-bolts are 2", but could be any size.

This tool could stand considerable refinement, but I was just wondering if a thing like this would work. It does, so I'm thinking about another model out of better wood which is a handier shape (shorter legs). So, if you make an improved version, please post pics.

I'm not planning to abandon my motorized belt grinder, but this device allows for a bit more precision and therefore minimizes the chances of grinding an edge bevel that is too thin. That happened with one of my khuks, and I don't want to repeat the mistake with my new GRS.
 
Nice project Cliff.

I do something similar when I'm in the field, away from the regular belt grinder. I just make an improvised bow, then string the sanding belt on the bow. Lash the bow to a downed tree, and voila, field expedient sharpening bench.

Of course, I went through a few sanding belts trying it out at first, but it's not like us knife knuts don't have old belts around to play with, eh?

Best way of attaching the belt to the bow that I've found were these little tarp clamps I found in either the Lee Valley or Garrett Wade catalogs(might actually be in both, I can't remember).

It's the most field-efficient way I've found of sharpening large blades(works great on axes as well, with a rough grit), and because I can adjust the tension easily (put a second tensioner on the bow, using paracord, allows the belt to have a little bit of droop, though if you've got enough flex in the bow, you really shouldn't need it) it works quite well for convex edges. I'll try and get some photos of the setup, but I'm not sure when the next time I'll be out in the woods will be.

TC
 
That is an even better idea, and it is good to know this use of grinding belts isn't completely off base. Part of what prompted me to make this thing was so I could have something behind the seat of truck which would work when I am away from the bench. However, the apparatus you suggest would fit in a small pocket of a pack, and that is even better.
 
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