Grizzly Belt Grinder

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These are a few photos of some of the modifications I have made to my Grizzly belt grinder. One photo shows a simple modification to the idler wheel to make it easier to remove belts. Other photos show how I added a third wheel to bring the grinding belt forward and a stronger platten modification for flat grinding. I have extra plattens with plate glass and hardened O-1 tool steel backings for smoothness and durability.

In some of the photos you can see how the tool rests (described below) work with the machine.

Also visible in the photos is the wooden shroud I built around the lower part of the grinder. This helps keep the dust down (on the back is a dust port hooked up via galvanized ducting to an industrial two-stage dust collector) and provides a little shelf space and a place for me to attach garage-sale-salvaged desk lamps for improved lighting.

I also have a plastic drywall mud tray that is filled with soapy water that sits just under the contact wheel and absorbs much of the dust as well.

I have designed a further modification to this grinder that will replace the shaft and motor with a new shaft, two pillow blocks, pulleys and a 2HP DC motor giving it variable speed capability and freeing up the Grizzly motor as a dedicated buffing machine. Another project that I have almost all the parts for, but just haven’t done it yet.

This is the tool rest I designed and built for the contact wheel on the Grizzly grinder. The tool rest is designed with an elevator to be able to move up and down by loosening a small set screw in the front to the rest. The tool rest can also rotate to form angles by loosening the socket head screw on the left side of the slotted horizontal slide bar. The slot in the slide bar allows one to move the tool rest in or out.

The only part that I have not added to the tool rest is a replaceable top plate for the rest itself, so when it gets a groove worn in it, it can be replaced without having to make a new elevator. These replacement plates will be screwed to the tool rest from bottom. In one of the above photos of my grinder, you can see the piece of metal that the slide bar slides onto. Two socket head screws secure it.

This is a second tool rest I designed to attach to the side of the platten. It allows precise angles against the platen and slides in and out to obtain different angles while maintaining a close proximity to the grinding belt. In one of the photos you can see this rest being used to precisely sand an angle on the front of a cocobolo handle slab.

This is a just a quick and dirty set-up I once used to slow down the Grizzly grinder, before I had a variable speed grinder. I just used a second 8″ contact wheel that I had in the shop attached to the buffing end of the grinder. I attached a small pulley on a motor shaft and ran a belt between the two. When I ran the motor, the belt travels at a much slower speed and gave more control for final grinding, etc. I would recommend you remove the wheel from the buffing end of the grinder when you run the main motor on it for high speed grinding; it will cause much vibration.

{ 5 comments… read them below or add one }

Mike March 15, 2011 at 10:33 pm

I just bought a Grizzly knife grinder and have seen some great knives made on it. Later down the road can’t I just switch the motor our with a VSM? I could only afford a Grizzly so what are the first things you would modify to improve this machine that wont break the bank?

Thanks Mike

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Brome March 16, 2011 at 6:57 pm

Actually you can’t exactly just switch out the motor for a variable speed one later because the drive shaft for the belt grinder runs through the motor to the drive wheel (the large lower one), and the vertical idler arm is bolted to the housing of the motor.

You can switch the motor, but it will take some modifications to the new motor (like the shaft so it will fit the drive wheel and figuring out how to attach the idler arm to it, for example). Another approach would be to make a new drive shaft for the main drive wheel that is mounted on pillow blocks bolted to a framework that can also support the idler arm and then drive this shaft with a pulley and belt going to your variable speed motor.

So it can be done, just might require a few more steps than a simple switch out.

As far as improvements, I would start by checking the alignment of the drive wheel and the idler. May seem simple but if they are out of alignment, it will drive you nuts as the belt will wander all over the place. Run a long straight edge between the face of both wheels to see if they are aligned.

As far as other improvements, those are only limited by your creativity, ambition and resources.

A key one for me was to create a box around it to channel the dust created into my collector, as well as hold a water bath under the drive wheel to catch larger dust particles. Not a direct mod. to the machine, but makes a big safety difference for me.

Lots of other ideas, but maybe that will give you a start. You can also see some of the other improvements I have pursued on my site.

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Trez January 13, 2012 at 7:18 pm

I am looking at belt grinders first how do you like the grizzle over the the variable speed one.

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brome January 15, 2014 at 6:36 pm

There just is no downside to having the flexibility of variable speed, and the KMG is one solid machine; a great design. But I still use my Grizzly regularly. It has its place in my shop and does well at what it can do. I am glad I started with the Grizzly, and still think it is a good starter machine, as long as you can accept its limitations.

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Darrell September 4, 2012 at 1:46 am

Finally got my Grizzly set back up after three years in storage due to a move. Can’t wait to turn out a couple of knives for the holidays. It would be great if you would put a a PDF sheet with the dimensions of the modifications you made. Thanks for a great site!

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