Contact wheel discussion

REK Knives

REK Knives

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Knifemaker / Craftsman / Service Provider
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I need to order another 4" wheel.... my polyurethane wheel from USA knife maker went bad after about 5-6 years (got all gummy and can be removed with fingernail). Was just looking at Bader contact wheels but they offer two different types of 'rubber'... neoprene and urethane. If I get one from them, which material should I get?
 
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Natlek said:
Polyurethane of course , if you ask me .What hardness they are ?
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I think I want to stay away from polyurethane... like I said it went bad after a few years. I wasn't sure if plain urethane is the same thing as polyurethane. I want to stick to good old rubber! You can select hardness you want. I was going to go for 70 probably.
 
If you think so ..........I see lot of industrial grinders around here . My friend have several big one .All of them have polyurethane wheels .On my 40 inch wheel I will use polyurethane and that was recommendation from experts I ask .
 
AVigil said:
Bader wheel for sure. They originated the belt grinder.
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Sorry I may not be making myself clear haha. Bader offers both (see here, scroll down a bit), I'm trying to figure out which material is best :)
 
REK Knives said:
Sorry I may not be making myself clear haha. Bader offers both (see here, scroll down a bit), I'm trying to figure out which material is best :)
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Give bader a call and tell them what you are doing and they can recommend one
 
I called bader... They said that the urethane is the same as the polyurethane and that the neoprene is the regular rubber. But they don't make them with a 1/2" shaft so they would have to custom make it.
 
I know this doesn't really answer the question and I know this is an unscientific and tiny sampling size. But earlier this year I made some 1" contact wheels out of neoprene and urethane. The neoprene wheels wore out and needed dressed every couple days. So, when I made the urethane wheels I went ahead and made three because I didn't think they would last very long and I'm still on my first one after making about a thousand knives with it and it hasn't even needed dressed yet.

Polyurethane comes in a lot of different flavors. I had a really crappy wheel from KMG that fell apart pretty quickly and I suspect it was cast urethane, although I don't really know, however the extruded urethane I bought from MSC seems to be better stuff. Although it's not very old yet so who knows.

Sorry if this doesn't really answer the question, but I have been marveling at the wear resistance of this polyurethane.


Edit to add: I say extruded urethane, but it could have been cast I don't really know. It was a hollow tube. *shrug*

Also edit to add: these materials grind really well. I was able to machine them on my lathe with a tool post grinder and I could not believe how well it responds to grinding.

Also also edit to add: I was able to attach them to the hub with regular West systems epoxy and it has held up just fine.
 
Nathan the Machinist said:
I know this doesn't really answer the question and I know this is an unscientific and tiny sampling size. But earlier this year I made some 1" contact wheels out of neoprene and urethane. The neoprene wheels wore out and needed dressed every couple days. So, when I made the urethane wheels I went ahead and made three because I didn't think they would last very long and I'm still on my first one after making about a thousand knives with it and it hasn't even needed dressed yet.

Polyurethane comes in a lot of different flavors. I had a really crappy wheel from KMG that fell apart pretty quickly and I suspect it was cast urethane, although I don't really know, however the extruded urethane I bought from MSC seems to be better stuff. Although it's not very old yet so who knows.

Sorry if this doesn't really answer the question, but I have been marveling at the wear resistance of this polyurethane.


Edit to add: I say extruded urethane, but it could have been cast I don't really know. It was a hollow tube. *shrug*

Also edit to add: these materials grind really well. I was able to machine them on my lathe with a tool post grinder and I could not believe how well it responds to grinding.

Also also edit to add: I was able to attach them to the hub with regular West systems epoxy and it has held up just fine.
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That's good info, thanks for sharing Nathan. I guess I didn't consider the possibility that there are different grades of polyurethane... The stuff I have that's degraded badly is made by Sunray.

Edit: I called KMG and the lady on the phone didn't sound too sure about anything, but she did say they use Mid American Rubber. So I called there and am waiting on a callback to see if I can figure out specifics on what KMG is currently using to see if it would hold up for me.
 
REK Knives said:
That's good info, thanks for sharing Nathan. I guess I didn't consider the possibility that there are different grades of polyurethane... The stuff I have that's degraded badly is made by Sunray.

Edit: I called KMG and the lady on the phone didn't sound too sure about anything, but she did say they use Mid American Rubber. So I called there and am waiting on a callback to see if I can figure out specifics on what KMG is currently using to see if it would hold up for me.
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This is my KMG contact wheel

Ig6jm6l.jpg



If you look closely, you can see that it has started to deteriorate enough that it could affect function. Because of this I haven't bought more contact wheels from KMG.


I think that Northridge seems to have pretty good contact wheels. I bought a 10" from them that works well and hasn't transformed into a fragmentation device.
 
Nathan the Machinist said:
This is my KMG contact wheel

Ig6jm6l.jpg



If you look closely, you can see that it has started to deteriorate enough that it could affect function. Because of this I haven't bought more contact wheels from KMG.


I think that Northridge seems to have pretty good contact wheels. I bought a 10" from them that works well and hasn't transformed into a fragmentation device.
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wow! Yeah I'd say that can infringe upon grinding just a hair lol

I wonder if they have always used the same wheel manufacturer or if they have switched... that's interesting! the 14" wheel I got from them in 2015 is still quite pliable and not gummy/disintegrating like my poly wheels from the same time period are. when was the above wheel purchased? Just curious!

yeah I would order Northridge but they only have 1 size of contact wheel unfortunately.

It's actually pretty difficult to find a good quality rubber contact wheel w/ a spacer in the middle these days... I'm probably gonna have to make a custom order through contact rubber corp. and make my own spacer.

Side note: my dad's neighbor bought that Mori CNC machine from you this past summer... small world :D
 
My KMGs are old. One is from the first week of manufacturing them. The original wheels are all fine. The 14" wheel I got when Rob started them is still fine, however long they've been available.

Time changes things, only sometimes for the better. I recently bought a work table for a disc grinder. It is, unfortunately, a good example of poor tolerances.
 
REK Knives said:
oh thanks for that! It looks like it would work w/ a 1/2" diameter bolt (which is standard here in the USA)... but it would have about .005" play on each side (13 mm bore is .511" inches)
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They use M12 bolt which is 12mm ? half inch is 12.7 mm ? You can enlarge that hole to 12.7mm ?? What I m missing ? What is that 13mm bore ?
 
Natlek said:
They use M12 bolt which is 12mm ? half inch is 12.7 mm ? You can enlarge that hole to 12.7mm ?? What I m missing ? What is that 13mm bore ?
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Here, this one says that it has a 13mm bore but uses an M12 bolt... it's strange, doesn't seem to match haha
 
Natlek said:
I miss that .But it is absolutely no problem , i would say you are lucky .That .005" play on each side don t matter at all ..........Look here why https://bladeforums.com/threads/how-to-mount-contact-wheel-on-belt-grinder.1771840/
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ahhh yeah that actually makes a lot of sense! I actually messaged that guy in Poland and he was very responsive... he said his brother is actually selling the parts in the USA so he sent me a link. Here's a better pic of the wheel so others can understand how it works

s-l1600.jpg
 
Contact Rubber Corporation will be able to help you out. Best in the business.
 
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