Polyurethane Contact Wheel
Idler type contact wheel with aluminum hub and 1/2" ID bearings.
Use a 1/2" shaft to mount these wheels. I use a 1/2" standard bolt.
We use Machinery Bushings (washers) that are 1/2" ID and with the OD just under the OD of the bearings. Use one on each side of the wheel and standard large fender type washers to center your wheel after that. You can order the machinery bushings from us or your local farm store may have them.
Aluminum core with quality bearings installed.
The tire is 1/2" thick. On a typical 70A duro wheel, you can push in with your thumb and feel a slight give right under the pressure point where it might flex a few thousands of an inch. 70A durometer hardness is what 95% of the knife makers are using for their contact grinding wheels.
These are a low cost substitute for rubber contact wheels. You can use these in the No Weld Grinder Plans. You probably couldn't tell these apart from rubber contact wheels comparing them side by side.
Polyurethane wheels are some what new to knife grinders but they have been around for decades in various forms and have a proven track record as contract grinding wheels. They do have a melting point of 185F degrees which is less than a typical rubber wheel so give the wheel a break to cool on extended grinding sessions. This is never going to be a problem for knife grinders but if I don't point it out, some one else will.
Someone will ask what is the quality difference between these poly wheels and the Beaumont Metals Rubber contact wheels you sell? Great question! Quality. These poly wheels are good, Beaumont wheels are great.
Beaumont Metals contact wheels use vulcanized rubber for their contact wheels which has been around for decades and has a proven, long term track record. The hubs are precision CNC milled and the wheels are trued up by Beaumont Metals. The poly wheels are good and becoming increasingly popular due to their lower cost. I'd suggest stepping up to the Beaumont rubber contact wheel for your main grinding wheel and filling in your wheel tool selection with poly wheels.
I use these on my own No Weld Grinders I have built.
NOTE: 6" Poly wheel pictured for illustration. Your wheel wheel may be slightly different in appearance if you get a different size.