There is not any bumper support on the sides with the wheels.
Ohh don’t most teams add like a piece of tubestock between each wheel anyways?
Yes, that’s one way to do it.
But I also know like 2590 only had corner bumpers, this is also legal?
Lack of bumper supports in the Versachassis model is an interesting reason to not do WCD. Might as well say it’s in violation of (2018) rules R63 and R64 because it lacks roborio and radio mounting.
We used versaframe components to make our 2016 and 2017 WCD. We liked how flexible we could be in bumper mounting by creating our own bumper frame to mount to.
Here’s a picture of our 2016 drive and bumper frame:
And here’s the next iteration of the concept on our 2017 robot:
Granted, there are other more tangible reasons to not do WCD. I believe we made the switch to WCD too early. In retrospect, we should have at least built a WCD prototype before our 2016 season so that we were aware of all of the subtle gotchas in part selection and mounting. We made several oversights that had the potential to kill our 2016 season that we should have identified earlier.
That being said, the AM 14U3 frames are still fantastic drivetrains. Very low maintenance, quick assembly, flexible enough for most teams, etc. If there’s any question about your manufacturing capabilities, the kit frames are the way to go. Spend your manufacturing time and money on the parts of your robot that play the game.
I agree that if one builds the VersaChassis exactly as per the CAD or your team has the ability to produce a high quality design that is easy to manufacture, you are correct that the time difference is minimal.
The challenge is when teams deviate from that basic design and essentially make a custom chassis out of it. That was why I wrote the second paragraph in post #15. I seen enough examples of teams struggling with issues such as inaccessible fasteners and over-constrained shafts.
Go for it! We made our first Vex-based west coast style chassis during a build season and never looked back. Fewer parts, easy to work on (especially wheels), and generally lighter. There are a lot of resources on Vex’s site and tons of people on this site that will help if you run into a snag.
As I tell all of the teams that attend the NASA Stennis Space Center Kick-Off; read the game manual, read the game manual, and read the game manual.
I was only answering the question as to why the chassis as pictured violated last years R32. The comment that prompted the question was to design with R32 in mind. So adding the correct tube stock could alleviate any R32 concerns.
So, if you go this route keep R32 in mind… Along with all of the rules that will be in the this years Game Manual (which may or may not include R32).
Also, read the Game Manual, stay current on the Q&A forum, and watch for the weekly rule changes. Knowing the rules and being able to show compliance with them is half the battle.
+1. We designed one VersaChassis WCD in CAD around this time last year, ordered parts for it around December 15th to receive them in time for kickoff, and tossed the whole CAD model out the window and started fresh when we learned the game (wanted an open front). We were still driving by ~1 week after kickoff. We had never built a WCD before. VersaChassis makes it ridiculously easy to assemble a WCD and configure it to your specific requirement. I’d still be recommending it to everyone I meet if the price hadn’t spiked.
Ever since the introduction of the VersaBlocks, there really isn’t a significant manufacturing challenge left in constructing a West Coast Drive-style drivetrain. So long as you do a little research and planning ahead of time in order to determine what parts you need to order, I don’t really see the need to prototype a WCD before you build one. Is it the choice for everyone? No, probably not. The AM14U3 is still a great choice for many teams. But the VersaBlock has gotten it to the point I can basically trust a sophomore with a transfer punch, cordless drill, and a step drill to manufacture our drive rails.
The one suggestion I will make is to use 3/16" rivets instead of 5/32" rivets for riveting together your frame rails. Super easy to drill out the pre-drilled 5/32" holes to 3/16" on VersaFrame and VersaFrame Gussets, though.
Can it be done? Absolutely!
Would it better to prototype prior to committing two teams entire seasons to being able to successfully pull it off quickly(less than a week)?
Most folks will say prototype in the off-season.
It all comes down to planning your work and then working your plan.
Ultimately, it is your team’s decision to make!
I’m the guy who brought it up. I wasn’t trying to suggest that a team should avoid versachassis because it doesn’t include bumper supports. My point was more along the lines of “If you decide to do versachassis, be aware that you’ll need to add bumper supports.” The photos on the Vex site of frames without bumper support are a bit misleading.
This year, I believe my team’s plan will be to reduce the width by two inches and mount 1" tubestock on the outside of the wheels to hang the bumpers on.
If you are looking for something with a bit more customizability than a traditional AM kitbot, but are worried about the resources required to machine a VersaFrame WCD, I cannot recommend the VexPro Drive in a Day enough! It gives you tons of choices for wheels, gearboxes, and mounting, but takes away the need to machine the frame itself.
We originally made our first West Coast Drive around this time in 2016, but rather than using tube, we used a piece of solid 2" x 1" aluminum. We messed around with it for a couple weeks, and as soon as we learned it was a flat field, we decided on using that drive train immediately, even though we had very little time to actually refine our design. We learned after we got to our first event a few things about the drivetrain, such as the diameter of the snap ring grooves we used being too small. We also learned things such as we needed to round down the end of the hex shaft between the groove and the end of the shaft, not just cut a groove in it. Little things like that gave us issues once in awhile, just little things going wrong, but in the end, we felt comfortable running the drivetrain and it never gave us major issues, even though most of the design was done during season.
Why do you need to round down the hex shaft at a snap ring? We have not done that, and I’m curious if there’s a reason why we should.
We used this chassis both as our drive base and for a lot of our robot structure in the 2018 season. The motor mounting options are awesome, and it allowed us to design a great climber in almost no time at all. Prototyping on it was a breeze and it only took about 2 hours for two rookies to assemble with minimal guidance. It also looks super cool in slick black powdercoat if that’s your thing. My only gripe with it is that disassembly to service wheels, drive pulleys, or gearboxes can be quite frustrating and takes a lot of time. Depending on your motivations for going WCD, this frame could be an awesome choice, or it could present the same issues as the AM14U3. This is definitely a product I think more teams could put to good use.
We realized 99% of the time when we attempted to put a 1/2" snap ring over the 1/2" hex (corner to corner becomes larger than 1/2") we would stretch the snap ring more than what it should be and it resulted in them being permanently stretched and popping off during a couple matches. It also turned out later that the spec we were originally using for the snap ring groove was the wrong diameter anyways too, having the ring just float more than being tight (as said by McMaster Carr Spec). We purchased 1/2" spiral rings we would thread on almost to fix the problem since we never really had a chance to take the axles off and turn them down to truly fix the issue.
Some teams may not have issues with it, but we’ve found turning the last bit between the groove and the end of the shaft down to 1/2" round just makes installing snap rings 20x easier.
As many have already mentioned, whether you do your own WCD or just use the kit base, speed is key. Not wheel speed, build speed. Whatever you do for a drive train it should be put together by Wednesday of the first week and not change after that. This way your programmers can get to work on autonomous, you can start dropping prototypes on to a moving robot sooner, and your drivers can start getting a feel for the robot sooner.