- Joined
- Oct 5, 2010
- Messages
- 1,045
There are a lot of posts on 2x72" belt grinders on this forum. These grinders are extremely useful in the shop, and I find mine, the most used machine in my shop. Just about anything I cut ends up with a pass or two on mine. I have found additional unanticipated uses, such as turning down rubber cylinders, grinding lathe bits, and other things I used to do on my pedestal grinder.
I am not trying to minimize the efforts of others, but it really doesn't require great design skills or big outlays of cash. You don't have to own a welder, but it helps to have access to one. If I were a professional knifemaker, I might opt for one of those high dollar units, but I am just a retired garage shop hacker and this serves all my needs at a minimal cost. 2x72 belts last a surprisingly long time as long as you don't poke through your belt. You learn quickly how to prevent that.
I was able to put this one together for @$200, a street find, and stuff from my scrap pile. My biggest expense was the 10" wheel that I bought off eBay for @$150. The street find was a treadmill with a 1.5hp DC motor and attendant electronics. I have minimal electrical skills, but there is a host of information on the Net to convert a scrap treadmill motor into a useful power source. Those motors run of 120vac power and you have variable speed capability. There is no need for 220 power, 3 phase motors, VFDs, multi-pully sheaves, etc. That brings the cost and complexity way down. So what I am trying to say is just about anyone with a small shop can build a 2x72 belt grinder. Just do a little research, go take a look at as many versions as you can (in person or on the net.) Just about anyone who has one loves to show his/hers off. Go visit a knifemaker or anyone who might have one. Then start collecting parts that might work. The biggie is the treadmill. I find that one shows up in my neighborhood about every 6 months. I now have a spare for future projects.
Other junked sports equipment can provide many of your structural parts. If you have a local scrap yard that will let you scavenge, you will have a gold mine for this and future projects. Craigslist, Freesale, 5miles, etc have free pick up categories that can provide additional opportunities. As you start accumulating parts, your design will change accordingly. Just be flexible, these machines can be pretty low tech.
I made the one pictured below within 3 weeks of finding the treadmill. Your design does not require heavy-duty structural components. Most of my components are thin wall tubing, pretty much tacked together. After 2-3 years of use, nothing has cracked or broken. The 1.5hp motor is adequate for the job. 2hp would be better, but the 1.5 was free. The variable speed electronics does the job to get the belt speeds I need. Just do the proper calculations so you get close to the midrange of belt speed with the pulleys you use. The belt tracking mechanism, which I thought would be difficult, was pretty simple in the end. The DC motors are not sealed and there is potential for grit/etc. to get inside, but I found that a simple metal shield over the motor has so far solved that problem. Cheap electronic project boxes adequately protect the electrical components. I have had no cooling issues. As you can probably judge from the pictures, space is a problem in my shop, so compactness was crucial to my design. The dimensions of my grinder are 41"x19"x22". That could be reduced some.
So stop procrastinating, start gathering some materials, design and build one. If you run into difficulties, there are people on this forum and others that will help you solve your problems. That is why you joined, right? In the end, the project will be very gratifying, and you will wonder why you waited so long. Besides, isn't something like this the reason you bought all those tools in the first place?
I am not trying to minimize the efforts of others, but it really doesn't require great design skills or big outlays of cash. You don't have to own a welder, but it helps to have access to one. If I were a professional knifemaker, I might opt for one of those high dollar units, but I am just a retired garage shop hacker and this serves all my needs at a minimal cost. 2x72 belts last a surprisingly long time as long as you don't poke through your belt. You learn quickly how to prevent that.
I was able to put this one together for @$200, a street find, and stuff from my scrap pile. My biggest expense was the 10" wheel that I bought off eBay for @$150. The street find was a treadmill with a 1.5hp DC motor and attendant electronics. I have minimal electrical skills, but there is a host of information on the Net to convert a scrap treadmill motor into a useful power source. Those motors run of 120vac power and you have variable speed capability. There is no need for 220 power, 3 phase motors, VFDs, multi-pully sheaves, etc. That brings the cost and complexity way down. So what I am trying to say is just about anyone with a small shop can build a 2x72 belt grinder. Just do a little research, go take a look at as many versions as you can (in person or on the net.) Just about anyone who has one loves to show his/hers off. Go visit a knifemaker or anyone who might have one. Then start collecting parts that might work. The biggie is the treadmill. I find that one shows up in my neighborhood about every 6 months. I now have a spare for future projects.
Other junked sports equipment can provide many of your structural parts. If you have a local scrap yard that will let you scavenge, you will have a gold mine for this and future projects. Craigslist, Freesale, 5miles, etc have free pick up categories that can provide additional opportunities. As you start accumulating parts, your design will change accordingly. Just be flexible, these machines can be pretty low tech.I made the one pictured below within 3 weeks of finding the treadmill. Your design does not require heavy-duty structural components. Most of my components are thin wall tubing, pretty much tacked together. After 2-3 years of use, nothing has cracked or broken. The 1.5hp motor is adequate for the job. 2hp would be better, but the 1.5 was free.
The variable speed electronics does the job to get the belt speeds I need. Just do the proper calculations so you get close to the midrange of belt speed with the pulleys you use. The belt tracking mechanism, which I thought would be difficult, was pretty simple in the end. The DC motors are not sealed and there is potential for grit/etc. to get inside, but I found that a simple metal shield over the motor has so far solved that problem. Cheap electronic project boxes adequately protect the electrical components. I have had no cooling issues. As you can probably judge from the pictures, space is a problem in my shop, so compactness was crucial to my design. The dimensions of my grinder are 41"x19"x22". That could be reduced some.So stop procrastinating, start gathering some materials, design and build one. If you run into difficulties, there are people on this forum and others that will help you solve your problems. That is why you joined, right? In the end, the project will be very gratifying, and you will wonder why you waited so long. Besides, isn't something like this the reason you bought all those tools in the first place?
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