[Madison]

It's exciting to see some people thinking in the summer

-will the hub be machined aluminum or some sort of plastic?
-what do you think the (approximate) weight will be per wheel?

- The hub is first being printed on a ZCorp Spectrum Z510 3D printing system, as it is a prototype. If there are no improvements needed, which certainly won't be the case, we'll likely be making the final hubs in an injection molding process.

- I haven't the slightest idea what they'll weigh, honestly. This isn't for FIRST use, so it's not a large concern.

One quick question: why the decision to use Phillips head? Will it be easier for personnel to change rollers?

Looks really good though. How big is it?

- The use of Phillips head isn't so much an intentional design choice as it is a matter of convenience. In some respect, I did consider that it'd be easier to replace the rollers if they were held in place by a common fastener, but it may turn out that we don't want them to be removable at all. Of all aspects of this design, the method by which the rollers attach is the least developed.

- The effective overall diameter of the wheel is 2.5".

Who is making the rollers for you all?

The prototyping is being done by someone that I met when I first moved to Seattle who was involved in SWAT Robotics - 824, a defunct team. He happened to mention to me that he was starting a prototyping business at about the same time I needed to start getting quotes for this wheel.

Sorry for the lack of knowledge...but what 3D modulation software was used to make these?

The models were made in Solidworks 2005 and rendered using its internal Photoworks renderer.

As you go forward, keep in mind the ratio of axle radius to wheel radius.

Are you referring specifically to the rollers, Joe? I presume you are, since the main hub is driven by a hex shaft.

The roller axle is currently planned as a 1/4" OD nylon tube and the rollers are to be urethane. As I mentioned above, this is the least developed part of the project at the moment and will likely pass through several more iterations before we decide on something that works effectively while remaining cheap to produce and easy to assemble.

Already, on the following revision, I cut back on the roller length and eliminated much of the taper that is shown above. That can be seen a bit more clearly on the image I posted of that revision found here: http://www.chiefdelphi.com/media/photos/25159?

That revision maintains the 1/4" OD nylon tube, but significantly increases the minimum roller radius.

Also, as a matter of full disclosure, I wanted to again reiterate that these wheels are not for FIRST use at the moment and will, instead, be used in some 'commercial' application. In other words, I'm getting paid to design this and, while I very much appreciate the criticism and advice, please be aware that you're doing some of my job for me. I know that some people might not want to do that