pic: 2 Cim, 6WD w/ Pillow Blocks



Just a simple drivetrain with a custom 1 speed gearbox. Has the gearbox on the front and pillow blocks to the back 2 wheels.

Very nice! I’d say the bellypan is a tad overkill - all you need is the diamond pattern. Here’s a quick and easy step-by-step tutorial based on how I learned to do it. I know some people also just use the vent tool in Solidworks.

Is there any reason you’re opting for the transmission to be in the back? It’s not a bad design decision and I’ve done it several times myself, but usually doing so has a purpose, and I’m kinda curious what yours is.

Last question - why are you using the custom sheet bearing blocks instead of the COTS bearing blocks? With how cheap and available the COTS solution is, I’ve personally found very little reason to make my own blocks for a WCD.

Overall this is definitely a great WCD - can’t wait to see more of what you make!

Agreed that diamonds could work just as well. That being said, the square pattern you are using looks easier to pattern.
I would recommend using Vex versablocks or the WCP bearing blocks, but if you have a CNC custom isn’t too bad. Just make sure you have a way to keep both sides aligned with each other. Back in 2014, 115 tried a WCD for the first time and had issues where the two would be offset relative to each other along the 2x1. So if you go custom, see if you can just make a copy of the Vex or WCP bearing blocks for the easiest effect.
Looks really good for a first crack at a WCD! The gearbox looks pretty clean as well, although you could definitely lighten it somewhat.

Nice drivebase!

Looks to me like the bearing blocks slide in the pocket for tensioning? We did something like this in 2016 because we used #25 chain, but we have since switched to #35 chain and now use the WCP bearing blocks. Would highly recommend this - just add .003" to C-C distance and you never have to worry about the chain again.

That diamond pattern tutorial is amazing, thanks so much for sharing that.

The WCP ones are supposed to slide. You oversize the pockets a little bit (I can look later and see what we used) and add a cam if you feel like it and then you can tension your chain all season long. Not sure why you’d really want to make them fixed, there’s nothing super wrong with that just not really how they’re meant to be used.

OP: awesome design! I’ll post some more comments when I get back from my bike ride later.

These are supposed to slide? Part number 217-3436.

Edit: I now see you can add a cam to the VersaBlocks… that must be what you are talking about. We use the side bearing block kit.

For #35 chain I would actually add 0.012" to the c-c distance. For #25 try adding 0.018" to the c-c distance. I can’t remember exactly where I learned this info from but there was some extensive testing involved in finding these numbers out (I think a youtube video and CD thread exists regarding this information). Also, I’m fairly certain Paul Copioli’s “useful calculations” excel spreadsheet includes these constants to add to chain direct c-c.

Adding that constant distance to each run of chain on a direct c-c gives you nice tight chain that you usually never have to touch after installation.

0.003" is for gears oops. (Currently working on a gearbox CAD so I have that number stuck in my head).

I second the idea of just having fixed positions rather than adjust tension. My team made a custom non-mecanum drivetrain for the first time this year and just went with #35 chain with a slight increase in center to center and we never had any issues. We had extra chain incase it was getting too loose but after making it all the way to Einsteins, we never had to replace the chain all season.

Yep… we use 217-3436 and they can and will slide. That’s one of the main reasons for using them. You can use the cam with them too (we didn’t however).

Our team made our own Pillow Blocks this year and they were probably the best thing ever! We intend to reuse them next year so I’m using them in my offseason designs aswell. I put the gearbox in the back because this is eventually going to be my go at a bot for 2014’s game, so I want to put my shooting mech in the front, so that the weight and space is balanced.