10-32 or 10-24?

[IndySam]

We standardized on 10-32 a couple of years ago and have never had a weight problem since. I would not recommend using both 24 and 32 because of the chance of mixing up hardware and causing problems.

Standardizing also reduces the number of tools needed.

[MrForbes]

We haven't really standardized on any particular size of hardware, because different things need different sized hardware. For example, mounting SMC solenoid valves requires 2-56 hardware, while mounting one end of our roller uses 1/2-13 hardware. We use several different sizes in between, too....5/16-18 for bumper mounts, 1/4-20 for several things, lots of #6, #8, and #10 screws to attach stuff to the plywood belly pan....and rivets in 1/8, 5/32 and 3/16" sizes of various lengths.

[Alan Anderson]

TechnoKats standardized on M3 and M5 for a year or two. It made finding the right tools trivial. We had a couple of plastic storage boxes with all the right drill bits and taps for the proper-sized holes. We had other storage boxes with a variety of bolt lengths.

I miss the simplicity of those days. I don't know what happened, but now we've got 10-32 and 1/4-20 and lots of other stuff all over the place.

[Phyrxes]

This is a transition year for us on a fasteners, as we have our first sheet metal frame. We went with a 3/16 rivet (using a number 11 wire gauge drill bit) which is slightly smaller than a clearance hole for a 10-32 bolt so we can drill out the rivet and bolt it if needed.

[AdamHeard]

#10-32 and 3/16" rivets.

1/4"-20 and #4-40 are stocked for places that need them, but we minimize there use.

Vex forced us to use some #8-32's.

Standard hand tools is nice, and lets us get a huge variety (L's, Ball end screwdicers, t handles, powerbits, etc...)

[Nemo]

Reason #3: 10-32 fits M5 nuts. The pitch is very slightly different, so this only works for a short threaded length. They fit together nice and tight. It works great with the nuts for 20 mm aluminum T slot extrusions.

Anyone is entitled to look down their noses at this practice if they feel so inclined, but our team has years of experience doing it without having bolt loosening problems. I got the M5 & 10-32 idea from these fine people, whose experience and expertise I trust very much.

[Mr. Mike]

Tapped holes in aluminum and plastic should be course threads. The screw is much stronger than the base material and a fine thead will strip out much easier. If you are bolting through and using nuts or tapped holes in steel, fine threads will give more strength.

[Dan.Tyler]

We standardize to the extent possible on 1/4-20 and 10-24, shcs or fhcs. The only exceptions are motors that require specific threads, or situations that demand a larger fastener (specifically a larger size, rather than higher strength)

The reason? Cost. In high strength fasteners, coarse threads are slightly cheaper. I doubt you could find a well designed FIRST bot where you need the strength of more than a quality 1/4-20 fastener. And the course threads give us the option of tapping into wood, polycarb, aluminum or steel without much issue.

Two box wrenches and two allen keys will take the bot completely apart and put it back together.

[JamesCH95]

We just standardized (mostly) to 10-32 this year and love it.

We have also started to use 10-32 riv-nuts for connecting thin materials and 10-32 t-nut inserts for connecting to plywood. Basically we wanted to have as many bolts as possible be removable with a single tool. It's worked out pretty well so far.

[FrankJ]

I would suggest that you pick & stay with one thread for each size screw. The day will come that some helpful person will dump the 10-32 nuts in with the 10-24 nuts, and then you will go nuts.

The nice thing about 1/4 is they have a broader range from acceptably tight to broken.

[JamesCH95]

Originally Posted by FrankJ

I would suggest that you pick & stay with one thread for each size screw. The day will come that some helpful person will dump the 10-32 nuts in with the 10-24 nuts, and then you will go nuts.

That happened to us... prompting the standardizing of 10-32.

[Matt C]

1/4-20 almost exclusively, all button heads unless the applications does not allow. We have a drawer filled with the correct sized T-handles and a bunch of 7/16" wrenches. Also have the same set-up for 10-32, but do not use them as often.
You still have the occasional student that has issues tightening stuff up only to realize that they grabbed a metric wrench from places unknown...

[Dan.Tyler]

It's shocking how well the metric wrenches fit in 5/32 and 3/16 hex heads...

[wireties]

1296 standardized on 10-32 5 years ago. Then we go one step further and use all black-oxide socket head cap screws. It helps with the weight had another unexpected side benefit - fewer tools required in the pit.

[Richard.Varone]

We primarily use 10-24, last year we considered switching to 1/4-20 but it ended up being overkill so we stuck with 10-24. But this thread has got me thinking, perhaps we'll give 10-32 a try next year.