VEXpro 2015 Product line launch

[AllenGregoryIV]

Originally Posted by tim-tim

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.

Why the fine threads?

[Lil' Lavery]

Originally Posted by Andrew Lawrence

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.

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.

[AllenGregoryIV]

Originally Posted by Lil' Lavery

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.

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.

[Mike Marandola]

Originally Posted by AllenGregoryIV

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.

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

[AllenGregoryIV]

Originally Posted by Mike Marandola

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

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.

[tim-tim]

Originally Posted by AllenGregoryIV

Why the fine threads?

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.

[asid61]

Originally Posted by tim-tim

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.

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.

[AdamHeard]

Originally Posted by asid61

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.

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.

[billbo911]

Originally Posted by AdamHeard

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

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

[magnets]

Originally Posted by AdamHeard

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.

1/4-28's? Where do we use these commonly in FRC? Bimba cylinders are available with this thread, but that's all I can think of for common parts...

[Thad House]

Originally Posted by magnets

1/4-28's? Where do we use these commonly in FRC? Bimba cylinders are available with this thread, but that's all I can think of for common parts...

It's the nuts on the breaker.

[Mike Marandola]

Originally Posted by magnets

1/4-28's? Where do we use these commonly in FRC? Bimba cylinders are available with this thread, but that's all I can think of for common parts...

Main breaker

[asid61]

Originally Posted by AdamHeard

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.

Whoops. I didn't know that electrical used those.
I stand corrected.

[Mr V]

Originally Posted by tim-tim

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.

I have found that Nylock nuts and bolts do not vibrate loose in FRC applications and if there is a situation where a Nylock is not suitable then we use medium strength thread locker. Once I introduced thread locker to the team there have not been any instances were a fastener came loose.

Where to you find rivet nuts that go in a 1/4" hole all the ones I've ever found use the annoying 19/64" bit. Because it is a less than common size we keep it in the kit with the rivet nuts so it is there when we need it.

[tim-tim]

Originally Posted by Mr V

Where to you find rivet nuts that go in a 1/4" hole all the ones I've ever found use the annoying 19/64" bit. Because it is a less than common size we keep it in the kit with the rivet nuts so it is there when we need it.

Yes, we have to drill the holes up to 19/64 as well. What I was trying to say is that even though the KOP chassis encourages 1/4" hardware, we still don't use it.

On a side note, it is always nice to keep a drill index on hand for things like this; but we to keep a drill bit or two in the bag with the riv-nut tool.