Temporary 2 x 72?

Well I wasn't going to post anything about this grinder untill I was sure if it was going to work but I decided to just incase someone was considering trying to make a belt grinder out of a treadmill. Hopefully this may help you decide if it is worth it or not. I know it has been done many times and there are youtube videos to prove it. I figured I would try it cause if it does end up working it will be a very inexpensive way to spin a 2 x 72 belt. So far i have:

$30 for working treadmill (Kijiji) sometimes you can find them for free
$45 for 4 skateboard wheels and set of bearings. Bearings were cheap ones incase it doesn't work.
$5 Screws, nuts and washers. I could have found them here but you will see in the pic below why it was easier to buy them.
$20 Couple pieces of square tubing and angle iron.

Last night I gave up on it because the way I had the belt set up it would not spin fast enough to make a spark. I ended up using the pulley/Balancer? on the motor itself because it was a bigger diameter. I got it spinning a bit past half speed and I was able to actually remove some material off of a knife blank I saw cut using the skateboard wheel as a contact wheel. Here is what I got so far.



The grinder is actually spinning fast enough in this pic to make sparks. As you can see there are more C-clamps holding it together than weld or screws. That's why I didn't want to go much faster. I am feeling pretty good about it so I will start welding it together making sure that I have everything as square, straight and parallel as possible. Tracking is a bit of a problem right now cause it is not square.

I still want to build the grinder I have been designing but I just don't have the time and extra cash to do it right. If this works out I will be able to take my time with my design and get the proper motor, VFD and wheels. Who knows, I may even be able to keep it as a lighter duty back up grinder. I'll keep you posted on how it works out and feel free to comment or ask questions.

 

Thanks. Going by the numbers the motor is rated at 4700rpm and the drive wheel is 5.75 dia so it should do about 7000 sfm max.

 

Ya I don't know if I will ever want to reach it. I guess I will have to see how it runs once it is welded and properly set up.

 

Thanks Jules. The wheels seem to be ok so far. I may have to get better bearings. These were only $10 for the set. To keep the dust out I was going to cover it with the original cover and cut some holes and put some kind of filter stuff over the holes. One other thing about the motor. I heard treadmill motors are over rated. Mine is 2.25 hp but it doesn't feel like 2.25hp. I hope to get it welded up in the next couple (work is interfering with my hobbies lol) days and see how much power it really has.

 

Thanks guys. Right now it is in many pieces. Last night I started cutting, fitting and welding the frame together. The way it was in the pic ihad to cut the frame to get the belt around the motor. I think I got that sorted out now but belt changes won't be as convenitnt as one of those fancy grinders but still shouldn't be too bad. I'll take more pics when I get the frame together properly.

 

That shaft is what I actually tried as to use as the drive wheel but it spun the belt way to slow. The frame itself is the main pain for the belt changing. Unfortunately I have to keep that shaft because there is a plastic wheel on th that spins inside of a sensor. Without it the grinder stops after a few seconds. Unless I can bypass the sensor somehow I have to keep the shaft. I even thought about shortening it but its probably not worth the time.

 

I was out in the garage for a bit working on the grinder and I'm glad I ordered belts today. It is not done yet but it is much closer. I have the frame and wheels square and straight to each other and it is tracking so much better now. I can actually track the belt to the left and right smoothly. For the most part the frame is in two pieces and just has to be welded together. Just a few nuts and holes that I have to take care of before I can finish welding. On the test run I had it screaming. Its pretty quiet for the speed it was going at and was smooth. I figure i had it at 3/4 speed and i think it is probably faster then I would normally run it at. I'm hoping I can finish it up tomorrow night and then I can post some pics.

 

Me too! I have to get it done and hopefully 5 blades out for ht Monday so I will be testing it as soon as it is together and safe to really use. I hope my 1 and only belt is nough to get the job done.

 

Thanks Jules. I just put some tape on the center of it. I may still crown it by hand though but if the tape holds up and works I may just leave it.

 

If you plan on using skateboard wheels I could only find them in sets of 4 so you will have extra wheels to try as a tracking wheel. You can find them on ebay for less than I paid for mine. I think I seen a set of 4with bearings for $25. They are actually long board wheels.