Re: VEXpro 2015 Product line launch
 

Regarding the new 1/2" hex VersaHub, is the new one just smaller and lighter and less expensive or is there something more meaningfully different?

PN 217-4009 - new product
PN 217-2592 - older product
http://www.vexrobotics.com/vexpro/mo...versahubs.html

If I recall, on the old ones the hex was not consistently clocked relative to the bolt pattern, so it wasn't possible to use two of them on one wheel. Instead you'd need to use one plus a hex bearing held in place with screws. I'm hoping this is what is different and the new ones, so that two can be used on a wheel and the hex flats all line up.

Re: VEXpro 2015 Product line launch
 

Hmm... do I spy a barrage? :rolleyes:

Re: VEXpro 2015 Product line launch
 

The new one is plastic so it's designed for lighter duty applications. At one point VEX started making all their Hex hubs aligned to the versakeys and I'm betting they still are, the plastic ones will definitely be aligned since they are molded. At one point they had to rotary broach some of their plain bore hubs to meet demand and those weren't aligned.

Re: VEXpro 2015 Product line launch
 

I guess I didn't look close enough. Never having purchased one I assumed all of these were plastic.

There does not appear to be a "light duty" designation for the plastic hub. Do you have any information on it's limitations? I'm wondering if using a pair of these on a 4" Traction Wheel would be an acceptable setup for a drivetrain.

Re: VEXpro 2015 Product line launch
 

I would say that the original aluminum would be better for drivetrain and other high load applications. These new plastic ones would work well in things like intakes where there isn't a lot of torque trying to break the hub apart.

Re: VEXpro 2015 Product line launch
 

You can always tap for a #10-32 heli-coil, threaded insert. I'm a #10 and #8 guy. If I had to use 1/4", it would be 1/4-28.

Re: VEXpro 2015 Product line launch
 

Why the fine threads?

Re: VEXpro 2015 Product line launch
 

Personally, I'd be less worried about breaking the hub apart and more worried about gradual wear along the corners of the hubs leading to backlash.

Re: VEXpro 2015 Product line launch
 

I agree, that is likely to be the first sign of a problem with these hubs. We used some .09 5052 versa hex hub stand ins on our practice bot and for part of an event on our competition bot and we rounded some of the corners and started getting a lot of backlash.

Re: VEXpro 2015 Product line launch
 

If that is the case, I would assume that it could be a problem on the colsons with the molded hex hubs as well.

Re: VEXpro 2015 Product line launch
 

I'm confident that VEX did their testing. I was just saying that I would think that would be the initial failure mode over completely breaking the hub. I could also be very wrong.

Re: VEXpro 2015 Product line launch
 

Just a habit of working on aircraft. The robots are vibration machines, so any little advantage to screws backing-out I will take. We have quite a few fastener stores in the area, so access to fine thread fasteners is not an issue.

That being said, we haven't used a 1/4" fastener on the robot in quite sometime - maybe a COTS component that required. We have used #10 rivet nuts in 1/4" holes in the past in the KOP frames.

Re: VEXpro 2015 Product line launch
 

An advantage to 1/4"-20 is that more teams that I know of stock it over 1/4"-28. Something to consider as well.
I don't think we have 1/4"-28 screws, just tons of 1/4-20", 10-32, 8-32, 6-32, and some metric.

Re: VEXpro 2015 Product line launch
 

Every single FRC team in the last 10+ years has had at least two 1/4-28 nuts on their robot.

Arguably the most standard FRC fasteners next to a philips head #6-32.

Re: VEXpro 2015 Product line launch
 

True, unless one student removes them and another replaces them with 1/4-20 nuts. Now that team has intermittent electrical problems as well.:mad: