What COTS parts would you like to see?

[Max Boord]

Originally Posted by jwfoss

Some offseason designs, and our limited in house capabilities leave us wishing for 1/2" hex stock with a pilot bore (aka Thunderhex minus the rounded corners).

Can you provide an example where the rounded corners make thunderhex shaft inferrior to regular hex shaft? Also thunderhex bearings alone should be enough of a reason to use thunderhex over Regular hex.

[Michael Hill]

Originally Posted by Max Boord

Can you provide an example where the rounded corners make thunderhex shaft inferrior to regular hex shaft? Also thunderhex bearings alone should be enough of a reason to use thunderhex over Regular hex.

We had a small issue this year. We were using the cheap-o plastic Vex hubs with thunderhex shafts in the front and back (6-wheel drive, center wheel had regular hex). We had 8" pneumatic wheels on a 16:1 ratio. We noticed the thunderhex shaft was rounding out the hubs. I think it was a combination of the plastic hubs, thunderhex, and high torque at the wheel axles. We took care of the problem by switching to the aluminum hubs and regular hex and saw no more problems. I couldn't tell you which one solved the problem, whether we would have had the same issues with regular hex with the plastic bores (possible) or the thunderhex with aluminum hubs (not likely).

The problem was not strictly with the thunderhex shaft, but in that particular application, using regular hex shaft would have possibly not worn out the plastic hubs (or at least would have delayed the problem).

[Knufire]

Originally Posted by Michael Hill

We had a small issue this year. We were using the cheap-o plastic Vex hubs with thunderhex shafts in the front and back (6-wheel drive, center wheel had regular hex). We had 8" pneumatic wheels on a 16:1 ratio. We noticed the thunderhex shaft was rounding out the hubs. I think it was a combination of the plastic hubs, thunderhex, and high torque at the wheel axles. We took care of the problem by switching to the aluminum hubs and regular hex and saw no more problems. I couldn't tell you which one solved the problem, whether we would have had the same issues with regular hex with the plastic bores (possible) or the thunderhex with aluminum hubs (not likely).

The problem was not strictly with the thunderhex shaft, but in that particular application, using regular hex shaft would have possibly not worn out the plastic hubs (or at least would have delayed the problem).

I think the official VEX recommendation is using a metal hub on one side (to transmit the torque) and a plastic on the other side to support the wheel.

[marshall]

Originally Posted by Knufire

I think the official VEX recommendation is using a metal hub on one side (to transmit the torque) and a plastic on the other side to support the wheel.

We had a similar issue and cracked the plastic hubs. Some very nice people with crazy pants on Team 1296 helped us out with some aluminum replacements. Reading that note on the Vex site is important.

[Michael Hill]

Originally Posted by Knufire

I think the official VEX recommendation is using a metal hub on one side (to transmit the torque) and a plastic on the other side to support the wheel.

I've never noticed that. Thanks for pointing it out. I knew you could get by with a single aluminum hub. I guess I misunderstood the purpose of the plastic one. In all honesty, they could just sell a plastic part with no versahub, just a mock bearing and it would work fine (and be cheaper to make).

[Michael Hill]

Basically a plastic version of this: http://www.competitionrobotparts.com...oller-end-cap/ with a 1.125" OD.

[Gregor]

Originally Posted by Michael Hill

Basically a plastic version of this: http://www.competitionrobotparts.com...oller-end-cap/ with a 1.125" OD.

http://www.andymark.com/product-p/am-1305.htm

[Kevin Ainsworth]

Originally Posted by AdamHeard

The attached gear was pocketed on each side .112, leaving a web thickness of .150.

Maybe leaving a little more meat by the gear teeth so you don't have a stress riser that can propagate to the thin web. We leave a 1/4" from the outside of the teeth to the OD of the undercut with about a 3/16" chamfer that cuts into the teeth slightly.
It looks like the broken gear has about 1/8" from the outside of the tooth to the undercut with about a 1/16" chamfer.

I also want Vex steel gears in 3/8" and 1/2" hex bores, 30 teeth and smaller.
We like to make the smaller gear steel and the larger gear aluminum. Aluminum on aluminum tends to wear out prematurely. Especially for the practice robot that gets much higher wear than the comp bot.

Originally Posted by jwfoss

-4"x1.5" and 4"x2" Aluminum Wheels with 1/2" Hex Broach
-Anti-backdrive stage for VersaPlanetary
-Disc Brake set up with 1/2" Hex or "Standard" Sprocket Hole Pattern

Anti-backdrive and a disc brake add-on for 1/2" hex stock would be a great addition.

Originally Posted by mklinker

I would like to see a ratcheting gear and pawl. It would be nice if the ratcheting gear had a 1/2 inch hex broached bore.

Option B would be a ratcheting gear with the standard FIRST bolt circle to attach to a hub.

Dido on the ratchet and pawl for a 1/2" hex bore. We modified McMaster ones for both our winch and climbing mechanism this year.

[AdamHeard]

Originally Posted by Kevin Ainsworth

Maybe leaving a little more meat by the gear teeth so you don't have a stress riser that can propagate to the thin web. We leave a 1/4" from the outside of the teeth to the OD of the undercut with about a 3/16" chamfer that cuts into the teeth slightly.
It looks like the broken gear has about 1/8" from the outside of the tooth to the undercut with about a 1/16" chamfer.

I'm pretty certain we actually failed that gear on the hex as it was pocketed way too close to the shaft.

there is actually a decent amount of material under the teeth based on what we've had work in the past.

[Michael Hill]

Originally Posted by Gregor

http://www.andymark.com/product-p/am-1305.htm

Wow! Andy's quick!

[Chris is me]

Originally Posted by Kevin Ainsworth

I also want Vex steel gears in 3/8" and 1/2" hex bores, 30 teeth and smaller.
We like to make the smaller gear steel and the larger gear aluminum. Aluminum on aluminum tends to wear out prematurely. Especially for the practice robot that gets much higher wear than the comp bot.

I've never had an aluminum gear "wear out". I've broken aluminum gears, I've run aluminum gearboxes for hundreds of hours on practice robots, but I've never had a gear "wear out". I'm sure you guys are properly greasing your gearboxes and taking all of the right steps for maintenance, so I'm really curious to see what your failures look like?

[Tal_Esh]

Not sure if was mentioned before but:

-2" omni and meccanum wheels, those are quite hard to find
-custom 971's-like roborio connections board
-more bevel gears

[Chak]

Originally Posted by Tal_Esh

-custom 971's-like roborio connections board

you mean this?

[Knufire]

Originally Posted by Tal_Esh

-custom 971's-like roborio connections board

This was designed by 971: http://www.wcproducts.net/catalogsea...ult/?q=spartan

[Michael Hill]

Originally Posted by Tal_Esh

Not sure if was mentioned before but:

-2" omni and meccanum wheels, those are quite hard to find
-custom 971's-like roborio connections board
-more bevel gears

http://store.kornylak.com/SearchResults.asp?Cat=20

We rolled the RW640s in 2015 for sideways motion initially. Didn't quite work out in that application (too slick). But 118 likes to use them for other applications. Check out the transwheels as well for light loading http://store.kornylak.com/SearchResults.asp?Cat=3