The Thrifty Bot: 2" Vectored Intake Wheel Product Updates

Alright, I’m a bit worried that I’m going to be declared a heretic for asking this, but what’s any better about these than WCP’s 2" mecanums?

Look at the prices

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They are $2.50 cheaper a piece. Is that alone what caused them to sell out in minutes?

I thought they used to be $40. Also, they’re a lot lighter than the WCP ones. They both likely perform the same. IMO, if you have a 3D printer just print the 125 wheel. If you go through the thread, there’s a file below that gets rid of the screws holding the two halves together.

I had my CC info stored in ThriftyBot’s system because I’d ordered from them before… I think people regularly underestimate the level of laziness process optimization I operate at…

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For some reason I thought the same. I think they might have brought down the price to be more competitive.

Anyone who needs some Thrifty wheels - two teams so far are selling some

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Are these wheels two parts or do the rollers just pop into place?

The hub has two halves that press fit together, and then are also screwed together to ensure the wheel stays together. The rollers are trapped between the two halves of the hub.

We ended up doing this too due to availability (or lack thereof) and the fact that we have a Markforge printer at our disposal. I’d definitely emphasize the “creative” part of your comment though, it was definitely one of the more interesting CAD exercises I’ve done (especially figuring out the screw-mounting method).

That said, the final product seems to work fine so far, though I would have liked to have an “official” set to at least compare them to. :expressionless:

I am totally going to try this, we have a mark2 and the HP in house. If the sponsor will let us, perhaps we can offer these to teams as well.

I struggled with projecting the 45 degree angle of the rollers onto the round shape of the housing, finally figured it out but it was not as intuitive as I am used to.

Yeah, I ended up separating the rollers in “pieces” to avoid cutting into the housing. After one of them was done though it was just a simple circular pattern operation to get the other 5 slots. Overall, it takes a bit more guesswork than I’m used to but I think they came out fine. :sweat_smile:

A couple of small tweaks for printing in powder and I think we might have something good. We will test tonight on a roller bar intake to see how the HP parts behave on the game pieces. @Ryan_Dognaux did an amazing job on this design. I think other types of VIW will be too sharp and poke into the skin of the ball and get stuck.

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If anyone has extra stock and willing to sell and ship us a set or two of these wheels please PM me thanks!

After we finished 2 full sets printed and dyed, these wheels perform really well! If a team was on the fence about buying them, this might help you decide:

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Do you have the CAD for this?

Have you tried fitting in two at once? I know that the lemons tend to be pretty sticky, which may or may not cause issues for your mechanism.

Yes we do have some test data on intaking multiples of up to 3. They prefer to stick to each other and go in as a glob with this intake style. This was our wood prototype that had some belting behind it to solve the traffic jam issue but we were not running that motor in the test above.

We are heading in a different direction on what is happening inside of the robot because of how badly these pieces stick together. They love to also wrap themselves around an axle if you intake them too fast. We have seen them slip through a 2" gap.

Like watching a rat the size of a football run underneath a door…

I think sorting these game pieces in the robot for us will look a lot different but our intake design is shaping up quite well with these wheels. We are going to test swapping the configuration and length of the roller bars in our next few meetings to dial in the best geometry.

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Possibly the most accurate description I’ve seen of what these balls can do :joy:

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Can you post that CAD?