My 2 x 72 belt grinder build

[Im4yotas]

I really love a good belt grinder, but have only owned a cheap useless one and always had the idea of building one myself kicking around in my head. This all started when I found a 3 horsepower 3 phase motor for $20 on craigslist.
I did some research, and there's a ton of good information on building these out there from the knife making crowd. So I picked up some wheels from various DIY knife places and a belt to do some mock up.

I really wanted to be able to get a nice long flat platen for straightening out rough cuts, but also be able to notch tubes, adjust a notch, or radius tabs easily. So I made a swivelling platen and wheel holder and did some more mock up.

 

[Death Row Dave]

Looks great , I have a motor and controller from a treadmill . Not sure how it will work or if at all . I’m wanting to build one of these also . It’s on my to do list , only number 1369 from the top .

 

[Im4yotas]

Looks great , I have a motor and controller from a treadmill . Not sure how it will work or if at all . I’m wanting to build one of these also . It’s on my to do list , only number 1369 from the top .

I was looking at the treadmill setup for a while, too. Seems like a good budget way to get variable speed. For my use, I really ended up liking the ac motor and vfd.

Once I got the main frame welded up, I did some more mock up to figure out motor mounting and tension/tracking, then glued it all together.

 

[Im4yotas]

I built a 2 way quick adjusting work rest arm, the tension arm and a stand. Then I decided to test out some paint schemes for the upcoming 4800 KOH build. This is where my wife went in the garage and thought she was walking into a scene from Dexter

 

[Im4yotas]

And here's the final product. Everything is tool free, quick adjusting (not shown in the pics, but all nuts have handles welded on). There is an automatic latch to hold the spring compressed for easy belt changes. The top wheel at the front is sized to match 1.75" tube, and the bottom wheel for 2". I can rotate the front plate for either wheel to be forward and get almost 180 degree wrap on the belt for full notches or radiused tabs.
I used a cheap $100 VFD from Amazon that takes my garage 220v in and puts out the 220 3 phase that the motor needs. It also allows variable speed control and reverse (if I ever need it?). The VFD is housed in the aluminum box for dust protection, and has a remote control panel that's next to the motor.
The motor is 3 hp, 3450 rpm, with a 6" diameter drive wheel which should give me just over 5400 surface feet per minute.

So far, I'm really happy with it. The 3 x 3 x 1/4" stand is a little wobbly, and sometimes the cheap VFD needs a kickstart to help get going, but otherwise it's great!

 

[kf4zht]

I might have to copy that swiveling wheel/platten holder. That looks perfect for what I need and saves me another fixture for radius grinding.

 

[rattle_snake]

Nice BG build. Have you has a chance to use it much yet?

I was lazy so just put a Coote on a stand and added a 1.5 hp motor (way more than needed). Will mow through 0.25 plate easily. I use the slack belt area a lot to debur odd shapes. Only complaint is that it is designed backwards for a right handed people, fuck them.
Best tool in my shop! Changed my life!

 

[bgaidan]

Nice build. Similar to the one I have, but yours is much cleaner and thought out. I bought this one for a steal on CL....cheaper than could have bought the parts separately. I've always planned to rebuild the frame to something more adjustable like yours. Definitely stealing the latch design on the tensioner.

3HP w/ a VFD. It's actually kind of terrifying when you ramp it all the way up.

 

[mobil1syn]

upcoming 4800 KOH build

get the thread going already

 

[Im4yotas]

get the thread going already

Yah, I probably will. Not much to show yet, though...

 

[Johann]

Very nice work! I have a Grizzly 2 x 72 that I use with the arm horizontal as a slack belt setup for sanding curves.

At some point I will go all the way down the knife making rabbit hole and build a good platten and support table to do that. That may end up being a separate rig like yours.

 

[Wheelerfreak]

I'm looking to build one myself, which site did you get our wheels from? I was looking at using a 110v motor and a V belt from that to drive the belt sander, but yours looks like a much simpler operation.

 

[Im4yotas]

I'm looking to build one myself, which site did you get our wheels from? I was looking at using a 110v motor and a V belt from that to drive the belt sander, but yours looks like a much simpler operation.

I got the tracking wheel and some idler wheels and contact wheels from OBM, aka Origin Blade Maker. The drive wheel is from Kadrmas Kreations. The idler wheels that I'm currently using are some I had machined for the specific radius that I wanted.

I stayed away from the 110v stuff just because I wanted to be 100% sure that I was not underpowered. I absolutely hate when you have to baby a belt grinder to keep it from stalling.

 

[Sterlingfire]

Damn do i need this, and your table

 

[Im4yotas]

Quick update on this - the motor has a problem on start up most times. It is rubber mounted and the mounts flex a ton when I hit start. The thing twists back and forward a few times quite violently and then the invertor goes into an error and stops. This can be overcome with a push start on the belt at the same time as hitting start. I suspect it is an issue with the cheap invertor trying to act like 3 phase on start up coupled with the rubber mounting.
The push start works fine, but it was making the whole thing shake on the stand. Apparently the 3 x 3 x 1/4" square isn't rigid enough. I added a little brace and that problem went away. Bolt on because I did NOT want to repaint it!