pic: FRC558's modified VEXpro Drive in a Day

[JesseK]

Originally Posted by TD78

I should clarify. I was not looking to form 3/8"-16 threads (or similar) using a die...I was thinking about drilling and tapping the ends of the steel rod (using a drill and tap). The rod would become a stiffening dead axle (although you don't advocate that practice).

Ah, I see. If you mount through the bolt rather than the axle (i.e. the mount hole is 1/4" rather than 3/8" and the 3/8" axle is the stiffening rod) then I don't know if there would be axial load on the bearings.

I would worry about the 1/4" bolt elongating the mount holes after a rare hit - like one that tips the bot up a bit, then the bot slams back to the floor, or like what happens when coming down off of a ramp/bump. We experienced some of this in 2007. When we went back to this style of dead axle in 2011, we used 3/8" rods and also used 1" angle brackets (1/8" thickness) to mount the wheels below the 1x1 frame. This gave us flexibility to change a mount out if we had problems. The "look" of the drive train where we mounted the wheels was similar to the old IFI KOP frame rails.

[jwfoss]

Thanks for the feedback, feel free to keep the questions coming. FRC558 was extremely happy with our drivetrain's performance and reliability in the 2014 season. There is something to be said for being able to assemble during week 2-3 of build and not have to touch the drivetrain for 100+ machines.

Originally Posted by TD78

Anyone have thoughts on using 3/8" steel rod as dead axles? Tap both ends of the axle and it'd be close to using tube axle/bolt. I wouldn't think a 1/4"-20 bolt would work...not enough thickness left in the rod. Something smaller like a #10 or #8...at which point you would have to drill all 4 holes in the DIAD sideplate, rather than using the pre-punched 1/4" hole for the outer wheels (of the 8wd)...but it could work.

I've looked into this, and would likely pursue it if we had the internal resources to machine them. At this time it would require relying on our mentors and sponsors to do work outside of the teams shop.

Originally Posted by AdamHeard

Did you guys slit the colson wheels at all? Or run them stock?

We run them totally stock, I don't believe the benefit is worth the extra work, however if we need more traction we'll look into it. We have never wanted more traction.

Originally Posted by R.C.

You can use the 1/2" I'D x 7/8" OD bearings as well. Allowing teams to use tube axle.

RC, have these bearings been tested for load? I'd love to run these but I have concerns about testing new things in our drives. If these are more then capable, we'll switch over to them and the tube axle material for 2015.

[puneeth.meruva]

do you guys think that there's any chance that FIRST will move back to a max of 4 CIMs instead of 6 CIMs?

[AdamHeard]

Originally Posted by puneeth.meruva

do you guys think that there's any chance that FIRST will move back to a max of 4 CIMs instead of 6 CIMs?

It's a possibility. Or some rule limiting max power in drive.

[Mr. Van]

Originally Posted by AdamHeard

It's a possibility. Or some rule limiting max power in drive.

We can only hope! With the introduction of so many powerful motors available, it's simply lead to a drivetrain power "arms race".

- Mr. Van

[BrendanB]

Originally Posted by bkahl

I'll be the first to attest that this drivetrain is a BEAST. For reasons I have yet to figure out, it could manhandle almost any bot on the field... Including 2 speeds.

Truth this setup was a beast.