Thanks, but we’ve already been in contact. We don’t desperately need the parts, and the customer service has been really great. Sorry for coming off as harsh.
This I get, and I must say, that all of the vex pro parts are just awesome in terms of tolerances.
You’re right about the concentricity. I was going to write about something else, but totally forgot to add it. The GD&T concentricity (average or median location of points on circle, I forget which one) is useful for shafts, as at high speeds vibration happens. We’ve only seen this being a problem when reusing custom gearbox shafts in high speed applications.
Tonight, out of curiosity, I measured a few parts to check the tolerances. I was unable to measure any runout on a hex hub we got today with some cheapo digital indicator. This is the first time I’ve ever seen this on an FRC supplier part like this.
I unfortunately don’t have PR people of my own, so I can only try to be as honest as possible about my VEXPro experience. Yes, I did consider that some teams may already have the specific cylinders required for the gearboxes. However, I did not and do not know how great that number is. Frankly, I assumed it would be a small minority of teams who choose to purchase a shifter from VEXPro. I’m curious to know if I’m wrong about this.
To me, and to several other posters in this thread, it was fairly clear that we had to additionally purchase a cylinder. I don’t think it was clear enough for everyone, though; oftentimes, what instructions are obvious to some can be missed by others. Example 1: the FRC game rules, and the numerous CD threads that follow Kickoff asking for clarification. Example 2: When my team purchased a Classmate laptop last year, the website came with an option to buy an AC adapter for the computer, in such a way as to imply that we needed to buy it separately. Eventually we found that this was not the case. Upon exploring the new VEXPro product pages, I got a similar feeling.
This, I believe, could be easily rectified with a few changes to the website’s formatting. First, let the defaults for the parts that need purchase be what most teams actually buy. I’ll use the 3-CIM shifter page as an example, because it has the most options. I notice that the default for “Base Options” isn’t “none”, but rather “3 CIM Ball Shifter Base Kit”. Similarly, the default for cylinders should be for 1 cylinder and 1 fitting kit. Second, options should not be completely hidden. Currently, when I change the radio button from “Base Kit” to “Base Kit with WCD 3rd Stage”, “3rd Stage Gear Kits” and “WCD Sprocket Options” appear. (I can’t select “Base Kit with 3rd Stage” at the moment, but I assume that only “3rd Stage Gear Kits” will appear.) This is a bit confusing for customers who want a third stage. Having the “3rd Stage Gear Kits” and “WCD Sprocket Options” sections be grayed out, rather than invisible, when purchasing the base kit or “None” would be preferable. These are both small changes, but they would make my buying experience better.
Are you stating that you purchased VEXpro items from us last year and they did not make it through last season? If so, then I am interested to know what products you are referring to so we can determine if that was normal wear or unusual circumstances.
I was talking about this year’s items, not last year’s. I simply meant that no new parts have been in competition yet, hence the “initial impressions” thread.
Concentricity is the median position of all the points on a cylinder, with respect to an axis. It’s extremely hard to properly establish. Total runout is almost always a better callout.
For those of you that use the other notation (like me), these are speed reducing, torque increasing gearboxes designed to make the motors “match” a CIM motor both physically and speed characteristics.
Can we sandwich a 4" VersaWheel between two HTD pulleys set up for 15mm belts, similar to what is done with the center wheel in the KOP drivetrain?
Essentially it will be pulley-wheel-pulley.
We don’t need a versahub in between, correct? Also, what size of #8 bolts do we need? The max on the Vexpro site is 2". This looks like it would be longer.
Paul, is the option of getting the cylinders still open? My team ordered a pair of 2-CIM ball shifters back in December when the website still said they came with cylinders, by the time they got to us though, the website had changed to say they did not, so we figured it had been a typo and did not pursue it further at the time.
Now, getting back to the subject of this thread, I will add a few thoughts…
This is our first year buying VEXPro products (aside from speed controllers); we started with a pair of 2 CIM Ball Shifters we ordered in December, and after being impressed with their quality and ease of assembly, we went on to purchase a pair of 3-CIM Ball shifters, 14 4" Traction Wheels, 24 50-tooth Gears and some Hex Shaft (all of which we plan to use to drive this). Here’s my personal opinions on each:
3-CIM Ball Shifters
Pros:
Lighter than alternative gearboxes
Seems to drive smoother than gearboxes we’ve used in the past
Small profile, given the whats in them.
Cons:
The assembly instructions were a little more confusing than the 2-CIM Ball Shifters.
The gearboxes seemed to have been shipped with the wrong size (too long) screws, which stick out through the hex (spacers?) too far and prevents the faceplate from being screwed on tightly. In our case our mounting system worked around this issue so its not a problem for us on our robot this year.
It would be nice if the 3rd stage versions came with an extra set of hex shaft spacers to allow for face mounting the gearbox while being supported from all 4 corners (We ended up making our own spacers out of AM Churro tube, which works fairly well).
It was not immediately clear how to properly mount the CIM gears to the motors and the instructions did not cover this step, the gears also appeared to not come with all the hardware to do so (of course this is based on how we’re used to mounting motors on AM gearboxes, so we could just be doing it wrong).
4" Traction Wheels
Pros:
Super Light, less than half of the weight of our previous custom aluminum gears of the same size.
Very easy to assemble.
Cons:
Mounting tread with rivets was a bit tricky since you have to use long rivets that also have wide enough heads to hold the tread on. We ended up having to use long rivets with small heads and using washers to keep the tread on. Some instructions on recommended tread installation methods and rivet sizes would be helpful in the future.
50-Tooth Gears w/ VersaKeys
Pros:
They’re so freaking light!
The versa keys were great for mounting the gears onto the wheels (using VersaHubs). The alignment looks great.
Cons:
A few of the gears had a hard time fitting onto the VersaHubs (not sure if this was a problem with the hubs or the gears though).
I’m not sure if they just weren’t available yet when we ordered the gears or if we were just looking in the wrong place, but in retrospect it would have been better if we had ordered some of the gears with 1.125" bearing holes instead of hex.
Hex Shaft
Pros:
Smooth fit onto our hex gears, works much better than hex stock we’ve gotten elsewhere
Cons:
It would have been nice if the longer length options were available (in stock).
It wasn’t clear at all. We ordered 2-CIM shifters on January 7. The bold, red text that you see now was not there. The description of the “pneumatic hardware kit” listed in the kit contents was not very descriptive at all and as a team that had never used shifting gearboxes before, we assumed the cylinders were included. The webpage has since been corrected, obviously.
We ordered early enough that we were able to place an additional order for the cylinders and had no problems getting the shifters or cylinders in a timely fashion.
I mentioned in my previous post that 558 is using a modified 2014 Drive in a Day chassis, attached is a picture of our practice chassis. We added the ability to run an un-equal spaced 8wd and bolted in some of the single reduction single speed gearboxes. We are very happy with how this chassis is performing. Please excuse the quality of the image.
I am slightly unclear on how VPs should be assembled given there is still documentation about the metal plate on your website. (In particular, the user guide which students used to assemble the motors makes no mention of the plastic plates)
Our gearboxes came with the metal and plastic motor mounting plates, they were assembled with the metal motor mounting plates. Is this a satisfactory motor mounting scheme with the absence of the bearing, or should they be swapped out for the plastic mounting plates.
Did something change with the VersaPlanetaries or were they always so easy to mate together with a BAG motor? We assembled them with RS-775 & RS-550 motors last year and still had some minor binding after several attempts from 4 different individuals. Both VersaPlanetaries went together very smoothly this year on the first try with BAG motors.
The new bearing gussets are very nice. The ‘end’ gusset is very easy to bend at the same point with imprecise equipment, allowing us to add a long roller intake on top of a plate.
We were happy to find the 7:1 VP ratio. It matched our intake roller speed to our drive train speed very nicely.
One product I’d like to see in the future is a 1/2" hex-hex shaft coupler. We’re getting away with a beefy 3D printed Nylon coupler on a low-torque application for now, but an Aluminum coupler with built-in shaft collars would be nice for high-powered applications. The printed coupler went through many iterations for tolerance, strength & brittleness before the final iteration, which works like a champ.
On another note, I’m surprised the teams surrounding the IFI warehouse aren’t screaming ‘free USPS shipping on a single low-value item if you send us team t-shirts or 3D print us something’. I wanted to order a 10:1 gear kit by itself and the shipping was more than the part. It wasn’t a huge deal - we tacked it onto a larger order a week later, but it also meant we got our production ratios a week later than desired.
Now that I’ve stopped in with a team that has some more vex parts, I thought I’d post my opinions.
Overall, the quality of the parts/packaging/documentation is very, very good. The ball shifter is small, light, and functional. It does a good job of shifting on the fly, and spends almost no time in the neutral position. Many of the products have very neat features, like the two sets of holes for the CIM’s to go with different pinions, and the really neat profile shift gears with different teeth and same pitch diameter. These are really neat parts to use in FRC.
There are two parts that I’m not a big fan of, and these are the 40 tooth dog gear, and some of the pinions. The bearings (which come pressed/locktited into the gear) stick out the end, which is a little weird. Once you pop the bearing out to replace it with one that actually fits, you’ll notice that the hole is oversize, and you’ll need to get some locktite. The dog pockets are also way bigger than they need to be. It would also be nice to see fillets on the 40 tooth gear like there are on the 44. I don’t have a vex dog with me, but the CAD model shows no fillets there either, unlike the AM ones. We’ve found that these fillets make a lot of difference. Those right angles are huge places for stress to concentrate.
The issue with the pinions has no easy solution and isn’t a vex problem, but the retaining clip for the CIM shaft has too big of an OD, so it catches on whatever gear the CIM motor is driving. This makes swapping out a CIM pretty tricky.
I agree with the mecanum wheel issue. There’s two ways these things fail. The rollers come loose, and the plastic wheel itself shatters. I broke a 6 inch one dropping it on the floor.
One more question for the vex guys, why is the slot in the dog shifting shaft so long? It’s significantly longer than the travel of the cylinder.
You’ll find that’s the case for most dog shifting gearboxes you can buy. I would assume it just makes the whole setup more tolerant inaccurate cylinder placement. Although I’d be curious to hear what the reasoning is from vex.
