VEXpro 2015 Product line launch

[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.

[MrRoboSteve]

Originally Posted by Mr V

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.

There's always the situation where a new team member uses the #10 nylock nut on the #8 machine screw. Kind of seems to work, if you don't pay attention to tightening it completely.

[ChuckDickerson]

Originally Posted by MrRoboSteve

There's always the situation where a new team member uses the #10 nylock nut on the #8 machine screw. Kind of seems to work, if you don't pay attention to tightening it completely.

One of our students did that back in 2006 with a bunch of the old IFI sheet metal wheels. That didn't work out so well until we figured it out. The sprockets all started falling off.

[RoboChair]

Originally Posted by Mr V

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.

Our 2007 Aim high robot vibrated 1/4-20 nylon lock nuts off... multiple times...

[Mr V]

Originally Posted by RoboChair

Our 2007 Aim high robot vibrated 1/4-20 nylon lock nuts off... multiple times...

Were you reusing the Nylocks? They are a one time use item, though you can often get by with using them a couple of times.