Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

That sounds robust. So the VersaHubs attach to the AndyMark hub assemblies for 8" pneumatic tires? I would think it simplest to use the 12-tooth sprockets with hubs, double for center wheel and single for the others with spacers to align everything, but there's probably a reason to use plate sprockets instead. I would love to see another photo if you do have a chance, it is very helpful to me as we try to sort through all our options.

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

You can actually press the VEX Versahub into the opening of the AndyMark hub because they're both 1.125" in diameter. The 6 hole bolt pattern lines up with the AndyMark hub and gives you a versapattern to easily mount plate sprockets to.

The smallest #35 plate sprocket VEX sells is the 22 tooth and that's what we went with. Anything smaller and you can't easily attach it to the wheel. We're running what is commonly referred to as 'dead axle' on the outer wheels - meaning we are just rotating the wheels on a shaft instead of rotating the shafts to drive the wheels.

I should also note that we had to drill out all of the VEX components because the AM hubs require a slightly larger diameter bolt. Not a big deal for us and it allowed us to use 10-24 screws to assemble everything.

Attached a few photos, one from our CAD that shows the wheel stack up and one I snapped tonight from underneath the drive itself. The CAD needs to be updated to reflect the use of 1/2 inch versahub sprocket attachment pieces and we didn't use all those hex bearings on the center wheel because it's unnecessary when you use 1/2" hex versahubs. The chains aren't very aligned yet and we still need to cut spacers for the dead axles that allow you to really clamp down on them, but we were able to clear all the static defenses tonight. Feeling good about the drive so far!

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

How did you attach the hex versahubs to the andymark wheel hubs? Our team is having a little trouble trying to attach those to our pneumatic wheel hubs (Andymark), we're trying to run these wheels on a custom chassis using chain also using the WCP SS.

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

Is it just me or does it look like the wheel valve stem will run into the drive plate?

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

They just pressed in for us, with a bit of force. A rubber mallet is a good tool to help persuade them. Make sure your 6 bolt pattern is lined up before you really get them seated all the way. You can put a bolt or two in to help keep them on track. I'd highly recommend taking a 1/2" hex shaft and make sure you can slide it through both sides of the versahub just as a test. Here's some clarification, let me know if you were asking about something else though.



It's definitely a tight fit but so far we've only seen some minor rubbing from our non low-profile nuts and bolts on the center wheel stack up. Once we switch to the correct hardware everything should clear completely. We ordered both the 1/2" and 1/4" spacer versions of the sprocket attachment versahubs and used the 1/2" version on the sides that includes the valve stem. On the outside wheels we just always made sure to flip the wheel so that the valve stem was pointing to the area with the most clearance.

The middle wheel is a bit of a challenge. The valve stem cap barely rubs on the chain, we're looking at different caps or a way to just keep the valve stem slightly out of the way.

Our team usually ends up packaging tight drive rails to free up more space on the inside. It means a little tighter work space if something goes wrong with the drive train but we've gotten pretty good at handling those situations.

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

Thank you for the clarification! I still have one more question (hopefully :yikes: ) that I'm gonna post here, since it might benefit other teams too.
What size bolts were you guys using to secure the hex versahubs to the hubs? Last night we were trying to figure out how to secure these to the hub itself, without the risk of the having the versahub fall out (or slip) and allow the wheel to get misaligned, free spin, etc.

Thanks in advance!

Re: WCP SS gearbox on AndyMark KOP chassis am14u3?
 

We used 10-24 bolts, I'm not 100% sure on the lengths though. I know we didn't have the correct ones on hand and just to get it done we got them assembled and then used a disc grinder to cut off the excess. I'll check tomorrow in the shop because I know the correct lengths came in for our competition version of the robot.