|Welcome to the “How to make a belt grinder” page. The fact that your here tells me a few things. You’ve probably already taken a shot at making a knife or you are ready to give a go and have started looking at the tools involved and the ridiculous prices for the most important tool.. the belt grinder.
If you are anything like me you are either broke, too cheap, or as I like to say (resourceful) to pay 2500.00+ for something I could make at a fraction of the cost…. So that is what I did. Below you’ll find detailed directions to build your own Belt Grinder including pictures of the one I made. Now I’m going to explain how I built my own belt grinder. I will preface this by saying there are MANY ways to make a belt grinder and this is just one of those ways. I made mine based off of the KMG design.
This post and the comment section below are not for negative comments. Constructive feedback is always appreciated and encouraged. Now lastly this is a step by step how to make a grinder. If you would like detailed CAD plans with specific dimensions feel free to go here to request plans in either PDF or DWF formats or click the link on the right side of the page. Also the dimensions I give are the one’s I chose to use. You can change them to work for you. Otherwise let’s get on with the show.
Base-plate – I used 1/4 inch steel I found for cheap at a scrap yard. It needs to be thick enough to handle decent weight and avoid flex. Steel square tubing.
Square tubing you need 2 sizes. Those two need to fit as closely inside one another as possible. The two I found were 1.5 inch with .09-.10 inch walls and the other was 1.25 inch I used 1 inch inner diameter
Threaded shafts – need 2 I used 1 inch diameter
Nuts and bolts – I used .5 inch nuts and bolts for the wheels and .25 inch for the pivots and tracking assembly. They need to be long enough to go through the tubing and whatever wheels you use.
Tracking wheel – I made my own tracking wheel. The wheel needs to be 2 inches wide and whatever diameter you choose. Mine is several inches with a 4 degree bevel from center. I turned a .5 inch center for the shaft.
Drive wheel – I made my own but it too needs to be 2 inches wide and whatever diameter you choose. I turned a 1 inch diameter hole for the shaft.
Bearings – You need 2 for the idler wheel (4 more if you choose to make a platen attachment) They need to be high speed and machine grade. I got mine at fastenal.
Shafts – You need two that fit in the bearings. I bought a mandrel set up that came with pillow blocks and shafts with threads and nuts.
Hydraulic trunk opener – I jacked one from an old car trunk. (used to create tension on the belt)
Light switch and switch house
Contact wheel – I got a 10 in wheel from grizzly for around 80 bucks.. (it’s the cheapest you’ll find em anywhere)
Motor and motor controls – I used a 2.5hp treadmill motor I got for free. I used all of the controls except for the potentiometer. The potentiometer was an old sliding version I replaced it with a metal twisting one. (Got it at radio shack for like 5 bucks)
Pulleys – need one for the motor and on for the drive shaft
Belt – one belt to connect motor to drive shaft
Steel bar – I used 1 inch wide bar 1/4 inch thick
Something to cut steel – I used a metal cutting band-saw and a grinder with a cut off wheel.
Welder – any welder will do I have a mig with flux wire (If you don’t have a welder there are no weld plans out there that you can make work with my plans)
Step 1 – Base plate and Base
The first step is to get everything cut and ready to assemble. Start with the base plate, mine is roughly 8.5 inches by 19 inches. The base I used was a big thick 4 inch piece of square tubing welded to the bottom of the base plate and then welded legs out of angle iron. Because I can’t drill into my garage slab and I needed the base to be capable of handling a good amount of weight without tipping. I welded 3 twenty pound weights together and then welded them to the base for stability. I also cut a few sections of 1.5 inch square tubing a few inches long each and welded them at an angle to the side of the base for an attachment holder.
Step 2 – Risers and pillow Block supports
As for the tubing you need 2 riser tubes. Use the 1.5 inch tube and cut it at 4 inches. Cut 2 – 1.5 inch tubes roughly 4.5 inches long for the back pillow block supports. I match the risers up with the front and back of the horizontal pieces and then welded them to the base plate. Make sure that everything is square. It makes a difference. I also made sure I left a 1 inch space between the front of the base and the first riser…. mostly for look but also I felt like it would be easier when welding and would lend to stability.. not sure the stability thing is true but it made sense in my head. The block supports are flush with the back of the base plate and spaced to accommodate the belt on the left and the drive wheel and belts on the right.
Make sure they are square and then weld them into place. Drill 2 holes through each support that match the holes in the pillow blocks. Secure the pillow blocks with nuts and bolts. Again make sure the shaft is square. Attach the drive wheel and move on.
Step 3 – horizontal pieces
Cut 2 – 1.5 inch tubes for the long horizontal tube (I don’t know what to call them…sleeve tubes?) roughly 13 inches long. These rest on top of the risers and are stacked on top of each other. You don’t have to run a bead down the whole side of the tubes to connect them. I chose 6 points about an inch wide at the front, back, and middle of both sides. Again make sure everything is square. The tension knobs I made with larger 1/2 nuts and bolts, drilling a hole through ONE SIDE (left side to avoid the belts) of the tubes. Then weld the nut over the hole and then put the screw in. Do this for both tubes and then you are done.
Step 4 – Vertical arm / tracking control
The vertical arm that makes the tension piece is actually 3 parts. You will be cutting the ends at angles. I don’t specify what the angles are because it doesn’t matter as long as the angle you cut allows the arm to swivel (see pictures for examples). You need a 1.5 inch piece of square tubing 3 inches tall one end cut at an angle. One piece of 1.5 inch tubing cut 2 inches also cut at an angle. The last piece is a 1.25 tube cut 8 inches long, one end is cut at an angle the other the corner cut off. Now if you compare the pictures to the plans (assuming you filled out the form to request the plans) you’ll notice I screwed up at the base. I cut the 45 angle facing the wrong way at the base of the vertical arm. Because of this I had to cut out the back of the base square tubing to allow it to swivel (Learn from my mistakes). Once the pieces are cut, weld the base tube on top of the horizontal tubes flush with the back. Place the long vertical tube inside the base tube and drill a hole with a 1/4 inch bit (only if you are using 1/4 inch bolts other wise match the drill bits to the bolt size) and then put the 1/4 bolt through and secure it down with a nut. The actual tracking assembly is simple but it works. Take the remaining 2 inch piece cut the back off the SHORTEST SIDE. Pick a place somewhere in the lower middle part of the LONGER SIDE and drill a 1/2 hole (assuming you are using 1/2 shafts for your wheels, otherwise match the shaft diameter) and push a bolt through. Put the piece over the top of the vertical arm facing right (the bolt should be sticking out to the right) and then drill a 1/4 inch hole through the top piece and the arm, push a bolt through and tighten it down with a nut. The top piece should now swivel up and down. Take note of where the head of the 1/2 bolt touches the arm of the long vertical piece. Now drill a hole through the arm and weld a nut to the LEFT SIDE of the vertical arm and thread the bolt through. The idea is that the bolt will push the head of the bolt on the top piece causing the assembly to swivel up and down. You may now notice that the head of the bolt on the top swivel lands on the vertical arm wall and will not allow it to drop low enough to get to level or below level. If we don’t fix this, the belt will track left and will not work. You can either drill a hole or cut a square into the right side of the vertical long piece so the head of the bolt on the swivel will drop inside it… problem solved. (see pictures for example.) As you may see I also welded a piece of round bar to the vertical shaft as a lever handle to pull on… not required but handy. I also welded round bar to the tops of all the bolts so I did not need a wrench to make adjustments. Now attach the tracking wheel and we’re moving on.
Step 5 – Motor mounting and hydraulic arm
The motor mount is simple. Actually…. it depends on the motor you use. The treadmill motor I had already had brackets ( angle bar) attached to it for the treadmill use. So I took two 1 inch wide pieces of angle iron and welded them to the underside of the base plate. Now placement for these is important… make sure that they are mounted so that the pulley on the motor shaft aligns with the pulley on the drive wheel shaft. I used 2 pieces of the 1 inch steel bar to connect the motor to the mounts. The length of the steel bar pieces completely depends on the size of the belt you will be using.
I think I had a 20 inch belt lying around so the pieces only needed to be like 6 inches long. This mounting system will use the motors weight to keep tension in the belt and will not require springs or additional weight. The hydraulic arm is also simple (in theory). The arm I had lying around had mounts that the balls on the arm pop in to. I pulled the mounts off and either bent or shaped them so they would sit flush where I wanted to place them. I them welded them to the frame on the left side of the top horizontal tube and on the side of the long vertical tube and then connected the arm.
This is what puts tension on the belt and allows a quick change of the belts. I used the original wiring from the treadmill except for the potentiometer. I bought a new potentiometer that was the twist type and just copied how the wires connected to the old slide type. I also stole the power cord from the treadmill and used that to wire to the power switch. I attached the power switch box to the support shaft and then wired everything through it. This allows me to be able switch the machine on and off.
Step 6 – Contact wheel attachment
The contact wheels attachment consists of a few parts. You need a base plate, 2 pillow block bearings, a square tube 4 nuts and bolts, spacers, and a wheel. I started by using an extra piece of plate and cut it just wider than the pillow blocks and long enough to cover the width of the square tube, the pillow blocks, and about 1.5 inches of space between them. A few things to keep in mind… Make sure you weld the plate to the square tube on the proper side. It should be flush with the side the belt is on. Second… don’t drill the holes in the plate too close to the square tubing wall so you can’t fit your nut’s on the bolt (I did and had to rework it… takes time). Drill 4 holes in the plate for the pillow blocks ( make sure they are squared) and bolt them in but keep them loose. push the shaft through the bearings and square it to the tubing. Tighten down the blots on the bearings. Now the spacers are needed to make sure the wheel is in line with the other wheels.
If it is off to the left or right your machine will not track right. I had some extra round stock I drilled a half inch hole in and used that. Put your spacers on and then put the contact wheel on. Bolt it all down and you are good to go.
Step 7 – Platen Attachment
The platen attachment is a bit more labor intensive. You need a plate (I used 1/4 inch). I cut min 13.5 inches overall and then I angled it back from the top and bottom. From the top I cut circles into the plate that recesses in a few inches. The total interior length is around 10.5 inches. I cut a piece of angle iron (the angle iron has a 2 inch face) around 9.5 inches long. I drilled two holes equal lengths from each other and then used a cut off disk to make a “track.” I then drilled two matching holes in the plate and put screws through them to connect the angle iron. The angle iron should now be adjustable in depth depending on the type of grind and the size of wheels you are using. I drilled two more holes and then attached the square 1.25 inch tubing (I cut 14.5 inches long.) I initially used long board wheels (two inches wide) and then ended up making two more for smaller diameter applications (You’ll see that in the pictures). I can now switch the top two wheels and run the belt across the wheels and platen or only on the wheels (good for inner radius like finger grooves). I used my lathe to turn the wheels and then bought bearings I could press fit in. As a side note. The long-board wheels are a cheap way to do this but the bearings will die… so be prepared to upgrade or replace the bearings. The bearings are cheap.. like 5 bucks for a set of 8 so it is your choice. It’s obvious but drill holes in the center of cutouts on the plate and attach the wheels. Make sure that the sides of the circles on the plate are BELOW the sides of you wheels. If the steel is above the wheels when you track the belt right or left it will ride on the plate and get cut up and die… no bueno.
Step 8 -Tool rest attachment
The tool rest is relatively simple as well. Again 1.25 inch square tubing cut to about 14.5 inches in length. You need a plate (I used 1/4 inch) cut 9.5 inches in length by 4.5 inches wide. I used 2 inch angle iron cut a few inches wide and welded it to the bottom of the plate. Make sure you fit the plate to center on the contact wheel. If you weld the angle iron to the center of the plate there is a good chance it won’t be centered. Drill a hole in the side of the angle iron that is hanging down and then cut a piece of bar stock roughly 4.5 inches and drill a hole at both ends (you may have to round the ends to get full rotation without getting hung up on the tool rest plate). I don’t specify what size holes because it’s really about what size nuts and bolts you have I had some 3/8ths hanging around so that is what I used. Drill a hole in the square tube and connect everything. This plate is fully adjustable up and down and in and out. You can make changes according to your needs and preference.
Step 9 – Now have fun
Now you should be able to throw a belt on and enjoy. If you have comments or questions feel free to post below or email me. Let everyone you know about us!