What does your team use for structural component hardware - 10-32 or 10-24? What are the situational advantages to each? Why do you prefer one thread size to the other?
In my experience, teams go-to hardware is almost universally 1/4-20.
Increasingly, teams are not using bolts in favour of rivets, though. Particularly those with sheet metal frames.
10-32 is normally used for machines, 10-24 is normally used for carpentry.
We use 10-32
10-32 for two reasons:
- 10-32 is the sze of the thread to mount CIM motors
- 10-24 and 6-32 are the most commonly broken tap sizes due to the ratio of pitch to shank diameter.
You already gotta use a bunch of 10-32s, and 1/4"-20 is usually overkill, so it’s the obvious choice. If you wanna use 10-24, have fun breaking taps.
The mechanical leadership on my team wanted to ‘standardize’ on 1/4-20 this year, until I pointed out that every COTS part we buy is 10-32. So we wound up having both, but standardized the lengths.
…and the science teacher who is helping us wants us to use metric hardware.
For our team we use a mix of 10-32 10-24 and 1/4 20
Lately however the last few years we have been using slot I aluminum pop rivets
Lighter save the weight
We tend to use 10-32 for most applications. 10-32 reduces the strength of the bolt less than 10-24 as the thread is shallower. They also loosen less easily as the thread angle is shallower.
We have large cases full of 1/4-20 and 10-32 nuts and bolts. 1/4-20 is for mounting to the frame, 10-32 is for superstructure and mechanisms. We’re gradually getting smaller in our fasteners…
There needs to be an option for “We have a can of assorted hardware that we pick from and hope fits.”
Our team uses both. #10-24 is nice for speed, but sometimes #10-32 are used for things like fine grain control or needing to get as many teeth in mesh as possible. I believe this year, our chain tensioning system uses #10-32 into a helicoil for these reasons. For our drive system, we typically rivet everything since we typically use a sheet metal base. We really try to determine what the right screw is for the job.
Up until last year, we had used 1/4-20 almost exclusively. We made the switch over last year to #10-32 and 3/16" pop rivets based on the recommendations found here on CD. I never thought we would go smaller until using the 2014 VEX chassis…we now have a large collection of #8-32 hardware. Haven’t had to go any higher than 1/4" this year, which is only used with the VEX “tube axle” (seriously love the concept). Definitely use #10-32 the most…small, lightweight, everything else others have mentioned so far.
We transitioned away from 1/4-20 several years ago for the weight savings.
10-24 hardware is easier to find/get. 10-32s require 33% more turning to thread the same distance compared to a 10-24. We use 10-32 when we interface with COTS items that use that pitch.
10-32. All the things others mentioned, plus you can tap them into thinner material and still get the required six threads of engagement.
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.
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.
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.
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.
#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…)