# Another belt grinder made from RYOBI bench grinder



## r3292c (May 3, 2019)

I needed a small belt grinder. So, I decided to build the one using my cheap bench grinder as a donor. I removed a rough grinding wheel on the right side. That’s a great place for the belt.

The motor isn’t really powerful – just about 250W. It runs at 3600RPMs. If I use 3-inch wheels to drive the belt, the linear grinding speed would be about 14m/sec, or 43feet/sec. I learnt that sanding wood typically requires 10-15m/sec speed, and grinding metals typically requires 15-30m/s. So, having 14m/sec on a 3-inch wheels seemed like a good trade-off for both wood and metal.

I found nice 3-inch longboard wheels I can use to rub the belt. The wheels are 2” wide, and 4” wide roller can be made from 2 wheels. This gives me the width of the grinding belt – 4-inch. What’s also interesting, when two wheels are tightened together, they form a barrel-shape roller because they have internal chamfers, and the edges of the wheels deform more than the body.



I picked-up 4” x 24” belt just because I needed a small grinder. Vertical and horizontal tables are made of ½” steel. The mounting plate is made of ½” aluminum.
























It looks like the belt isn’t running fast on a video. That’s because of video frame rate, it runs fast actually. The sides of the cube are flat, and the edges are sharp as a knife! I’m happy about the grinder!


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## David S (May 3, 2019)

Nice going and also nice pictures.  I have a project to post soon but I need a better camera (person ?).

David


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## tweinke (May 3, 2019)

Nice build!


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## larry4406 (May 4, 2019)

Very nice!

On the drive wheels looks like you removed the bearings and used an arbor that you turned?

How does the tracking knob work?


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## r3292c (May 4, 2019)

larry4406 said:


> On the drive wheels looks like you removed the bearings and used an arbor that you turned?
> 
> How does the tracking knob work?



Yes, sir
The bearings on the drive wheels were removed. The aluminum arbor is used. The screw on the arbor's end tightens two wheels together providing a barrel shape with a hump in the middle of the roller.

The tracking knob is a simple 1/4" screw with a knurled knob on it's head. By screwing it in/out the angle of the tension wheel is adjusted.


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## larry4406 (May 4, 2019)

How do you tension the belt?  I see a spring in your last pic.


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## Tozguy (May 4, 2019)

Great design, clean and simple, love it!


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## r3292c (May 4, 2019)

larry4406 said:


> How do you tension the belt?  I see a spring in your last pic.


Yes, 5/8 x 2-1/2 x 0.72 spring from Home Depot. It creates 19 lbs work load according to Spec.


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## larry4406 (May 5, 2019)

r3292c said:


> Yes, 5/8 x 2-1/2 x 0.72 spring from Home Depot. It creates 19 lbs work load according to Spec.


How does the spring tension the belt?  Is the tracking head pivoting on the bolt like an eccentric?


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## r3292c (May 5, 2019)

Yes, the tracking head is pivoting on the bolt like an eccentric.


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## larry4406 (May 5, 2019)

r3292c said:


> Yes, the tracking head is pivoting on the bolt like an eccentric.


Thank you.  I want to build one of these.


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## FLguy (May 5, 2019)

Very professionally done.


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