Zero wear.
At 2-7/8" we ran them up to 13,000 RPM with no problems, though our normal operating speed was around 10,500 rpm. That works out to almost 10,000 surface feet per minute. The same surface speed for the 4" wheel would be roughly 9000 RPM, though it’s going to expand more and give you a higher effective surface speed.
I know 233 accidentally ran a 4" one up to 13,000 and it exploded nearly immediately.
We’ve been running a pair of these wheels since Wednesday evening of the Championship in our shooter and they’re probably the ‘best’ shooter wheel we’ve found thus far.
Couple of notes:
Also, add us to the list of those who have had a wheel fail from spinning it too quickly. The Second wheel on our shooter spins somewhere around 11,000rpm at 100% (which is way outside of our normal operating speed) and during testing, we had one of the wheels start to rip itself apart. I have a picture somewhere, if I find it, I’ll post it here.
You can turn them on a lathe with a properly ground, very sharp HSS tool.
i would love to try the mcmaster wheels, we used the banebot wheels as the wear was pretty bad, we had to keep replacing them about twice an event.
I think we would have noticed if our wheel wasn’t concentric. Our shooter ran very smoothly without much noise.
I think the reason these wheels fail is largely a function of time. When prototyping we ran a 4" 1:1 off a 550 for a few seconds and the wheel was fine.
Every we shot our wheel would expand considerably, and the stress of the repeated expansion coupled with how fast we were running the wheel was what caused it to fail. Like I said the failure is a function of time, not just speed.
I believe the urethane wheels are bound to fail at some point when run at FRC speeds. There’s no magic rpm that they fail at, it’s just a question of how long you want them to last. If you run them at 10,000 rpm or slower they’ll probably last a season, anything faster and you’re pushing your luck.
Inquiring minds want to know:
How are 1114 and 2056 getting their hands on McMaster parts? I’ve tried to order from them before, and they just tell me they won’t ship to anyone who isn’t an existing customer in Canada.
Are they getting IFI, or some friendly american team to buy for them?
We’ve had a McMaster Carr account since 2007. This must have been before their policy not to accept new Canadian customers. Their customer service is second to none. My advice would be to email them explaining your situation(being a highschool team, exposing future engineers to their company, blah, blah, blah), and ask them to open an account for you.
Either that or find a local company that already has an account and doesn’t mind sliding a few parts in with their orders.
Ah. I figured that might be the case for 1114, was unsure when the ban on new Canadian accounts started, but it seems like it was somewhere in the neighborhood of 2009 from what I can find based on Canadians complaining on online forums about it.
Does anyone happen to have a weight on these wheels?
They’re not interested. Future engineers, we’ll pay you, and others teams spend x dollars annually didn’t help.
We had a friend in the US try and order some blue nitrile for us, and even then they wouldn’t ship it across the border.
I know my employer has an account. I’m sure I could convince my boss to let me piggyback some stuff on an order if 4343 needed something and couldn’t get it somewhere else.
From what I recall they got busted under the Patriot Act for selling something that has 5 million and one different uses (with only one of them being dangerous)to people in the Persian Gulf.
After that they must have decided it was easier to not deal with any new foreigners. From what I understand they are very rigid in this policy, even sometimes refusing to ship orders that look like they’re headed to a border town to be brought over into Canada.
our rookie team was able to create an account and put orders out.
we have had some of our orders denied when we set the shipping address to a mentors house, but when we ship it to the school there are no problems.
Actually our first order was refused because we were not a long standing Canadian Customer. So I ordered and shipped to a US mail box once. Then the next fall tried again, and voila, we were a long standing Canadian customer and have had our orders delivered to the school next day ever since.
apparently if you state that the order is going to a school address for FIRST robotics it will go through.
So is there not a best compression to the disks? Or is it 1/2in to a 1/4in?
You’re going to have to try it and see. It’s completely dependent on what the surface opposite the wheel is. There’s no shortcut for testing it yourself.
Sweet thanks for the info! I am trying to get access to my teams parts and robot… They are both in a chemistry closet right now 
We are going to test them soon though.
Anyone try these with a cut down version of the WCP colson hub? It looks like the OD of the hub might be a bit to small but I’m not sure.
We haven’t, but it should be super easy to make a hub. You turn down 1.375" or 1.5" stock a bit, bore, and then cutoff. Later you broach. Assuming you have a lathe and arbor press it is super easy to do.