42" belt grinder build

[Phillip Patton]

Hey all,
It's been a while since I've done a tutorial of any kind, and I'm in the process of building a little grinder, so I thought I could turn it into a wip if there's interest.

 

[Techtical]

When in doubt WIP it out.

 

[phorizt]

I'm about to start building a grinder so I'd love it if you did a WIP. Just curious why are you building a 42" grinder?

 

[12345678910]

When in doubt WIP it out.

Funny but true

 

[VaughnT]

I'd certainly be interested in seeing what you come up with. I'm in the process of trying to build a work rest for my kmg-clone and love to see what other folks can conjure up.

 

[nthe10ring]

Sounds great, looking forward to the build along.

Jerry

 

[SinePari]

I'm down to witness any WIP you have to offer. Look forward to it to tell you the truth!

 

[Phillip Patton]

Ok, here comes. I'm just going to use this thread for the build rather than start a new one. I've changed the title to reflect this.

Someone asked why a 42" grinder? I wanted a smaller grinder that I could take to shows (if I ever go to any) and use for sharpening knives for show-goers. But I don't like any of the 42" grinders I could find on the market, because the way they are designed doesn't work with the way I sharpen. While planning this grinder, it occurred to me that I could also use it for the handle finishing operations that I currently use my KMG for (I use scalloped 1" wide belts for that), which would save me some time changing tools.

The first things I made were the tooling arm. I used some 1-1/8" square stock that I've had for years. It's 12" long:

For simplicities sake pretty much all the bolts used are 3/8" NC:

Then the aluminum part that holds the wheels. I made this one with 8" between wheel centers, but I may be replacing it with one with 6" between centers. I'd also like it if it were a little "deeper":

 

[Phillip Patton]

I had to buy all the metal part except the tooling arm. I got most of it on ebay, since they had the best prices. The next parts to arrive were the steel bars for the part that holds the tooling arm:

I clamped the parts to the tooling arm to keep it square while welding:

I just tack welded it for now, to keep distortion to a minimum.

 

[Phillip Patton]

The next thing to come was the aluminum for the wheels. I'm not going to post any pictures of wheel making, because I would recommend buying them somewhere, unless you are a machinist, in which case you don't need me telling you how to do it. I thought I'd save some money by making them, but it was such a pain I would never do it again, at least with the lathe I have now. Making the 3" drive wheel pushed the lathe all the way to it's limits, and beyond.

But here's a picture of the (mostly) finished product. The three idler wheels are 1-1/2" diameter. All are 2" wide, so I can use either 1" or 2" belts.

I chose the motor speed and drive wheel diameter to give me a SFPM of 32,499. This is the same as the middle position on my KMG, and it's the speed I use for sharpening and slack belt grinding. I considered going with a variable speed setup, but decided it wouldn't be worth it for this grinder.

I decided to not make this grinder with a tracking system. I won't be using it for stock removal, so I didn't think it would be worth it. Instead, I'm crowning all the wheels.

 

[Phillip Patton]

Next came the steel for the base plate/frame and the motor. How tall the frame needed to be was determined by the physical size of the motor, which is about 7" in diameter.

I bought the motor off of ebay as well. It came from Texas, but originated here in Fort Wayne.

Now the parts for the frame are cut to size:

and the holes for the motor drilled:

Then the tube for the tool arm is welded on to the frame upright:

Then the mounting holes are drilled in the base plate:

And the two parts of the frame are welded together:

Here's the tool arm and motor installed:

 

[Phillip Patton]

Next the bracket for the idler arm:

Now the idler arm is made.

These discs are to hold the spring in place:

The top one is welded on, the bottom is held in place with a pin:

 

[Phillip Patton]

Then all the wheels and other parts are installed. I don't have any 42" belts yet, just a dummy belt I made from a 72" belt, so I can't really try it out, but it looks ok so far.

While the belts are on their way, I'll paint the machine. That's all for now. Any questions?

 

[Phillip Patton]

Two coats of primer:

and three coats of paint. I used dark gray "Hammered finish" Rustoleum. Notice the hammer marks.

I also made a handle for the idler/tension arm:

 

[BallewBlade]

I think that grinder is going to work perfect for what you need it for. Thanks for sharing, I am also in the process of making a grinder, although its a 2x72. I'm curious to see how your grinder will work without a tracking system. I'll stay tuned! :thumbup:

 

[Phillip Patton]

After letting the paint harden for a couple days, I've now assembled the machine. So here's some finished pictures:

 

[Phillip Patton]

I rigged up a dummy 48" belt to see that size would work, and it does.

 

[Maelstrom78]

Cute as a button! Looks very well built.

Makes me want to get one for my 3 year old to start practicing with.

 

[tiguy7]

Looks like a solid rig. Does your grinder work best for convex edges?