Standardization of Hardware

FIRST General Forum
#1

As we head into the offseason and everyone is gearing up to make improvements to their teams and processes I’ve got some queries in terms of robot hardware bolts, rivets, etc.

Does your team standardize hardware and hole sizes?
If so what do you buy in terms of drills, allens, bolt lengths, etc.?
If you aren’t standardized how do you maintain the various bolt sizes and holes etc.?
If you are using rivets do you just eyeball it and drill them out or do you have a tool for that specifically?

I’m trying to get my team to standardize 10-32 bolts since the close fit size is the same as a 3/16 rivet. Not sure what to get as far as just bulk buying L allen wrenches from McMaster or something else.

Here’s to bigger and better things!

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#2

I thought having hex flange head screws would be a step up for our team, but they really didn’t catch on, despite my buying a huge range of them and stocking up on nut drivers… I hate the button heads due to the tiny allen key, but they kids and other mentors keep using them and buying them. I guess on the bottom of the belly pan the rounded head is sorta nice. One thing that was super frustrating on the hex flange head is the stupid head doesn’t match the nut :frowning:

1 Like
#3

Standardization helped our design process a TON - we threw out a lot of things that we never use and sped up decision making a lot. Here’s some things we’ve standardized for on-hand things:

  • Bolts - with some small exceptions, assume 1/4-20 if it’s drivetrain, assume 10-32 if it’s not. We have a bunch of lengths on. hand and only buy specialty bolts/buts if needed.
  • Sheet stock - ONLY 1/16", 1/8", or 1/4" AL6061 or Polycarbonate.
  • Box tubing - assume 2x1 or 1x1 (unless something requires different sizes like a telescoping arm). 1/8" wall for drivetrain, 1/16" for everything else
  • All box tubing for the 1st iteration robot gets the same hole pattern - clearance holes for a 10-32 bolt (can be drilled out if needed) that are 1" apart on the sides and tops. This also allows for 3/16" rivets.
  • Shafts are assumed to be 1/2" Thunderhex, retained with circlips

All of our robot frames are 90% box tubing + gusset, but it helps the kids get to functional products faster. I’m sure there’s more things we standardized, but that’s all off the top of my head.

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#4

We use mostly #10-32 hardware and some 1/4-20

For the #10-32:

  • Use #9 drill bits to drill close fitting clearance holes 30585A19
  • Use #21 drill bits to drill for tapped holes 30585A33

For the 1/4-20:

  • Use F drill bits to drill close fitting clearance holes 30595A71
  • Use #7 drill bits to drill for tapped holes 30585A17

For rivets:

  • 97447A060 for 3/16 holes .376-.5 material thickness
  • 97447A075 for 3/16 holes .376-.5 material thickness (large head for lexan fastening without washer)

For Tools we have at least 4 of each of these:

  • Ball-End Hex Screwdriver 1/8" Size, 6-5/8" Overall Length 5497A27
  • Ball-End Hex Screwdriver 9/64" Size, 6-13/16" Overall Length 5497A28
  • Ball-End Hex Screwdriver 5/32" Size, 7-15/16" Overall Length 5497A29
  • Ball-End Hex Screwdriver 3/16" Size, 8" Overall Length 5497A31
  • Nutdriver 3/8" Size, 3-1/4" Bolt Clearance 8358A27
  • Nutdriver 7/16" Size, 6" Bolt Clearance 7142A16

Here is our full list of items we try to stock:

6 Likes
#5

is the 1/4-20 needed for drivetrains or is it more of an overspecing for 1000000% peace of mind guarantee? Im thinking if I can get away with only 10-32 Im gonna want to.

2 Likes
#6

10-32 socket heads and 1/4-20 button heads both use a 5/32" allen key. This makes your life much easier.

17 Likes
#7

About ten years ago we noticed this, and a corresponding demand for 5/32” T-handles.

#8

We use 10-32 and 1/4-20. Something we stole from FRC1501 (and others) is putting some green electrical tape around the #10 tools and red electrical tape around the 1/4" tools. This makes it super easy to quickly identify the needed tools.
Highly recommend these offerings from AndyMark:

3 Likes
#9

Mostly peace of mind. It may be overkill for some designs, but we haven’t had any serious weight concerns yet, so there hasn’t been a need to try reducing.

#10

10-32 and 1/4-20 button head screws for screws. 5/32 rivets because we use versa tube (although REV ION may change this for us…).

1/2", 3/4", 1", 1.5", 2" is our standard stock of 10-32’s. The same selection of 1/4-20’s with the addition of 2.5" and 3".

Any other size bolt deemed necessary in season is purchased on a case by case need.

0.188-0.25", 0.251-0.375" and a few 0.376-0.5" grip range, 5/32 rivets. Mostly aluminum, but some selection of steel rivets kept in stock too.

We keep a selection of the following drill bits:

  • #9 for for 10-32 clearance holes
  • #21 for 5/32 rivet holes (a 5/32 drill bit will normally create holes ever so slightly too small for a
  • 5/32 rivet. Switching to #21 bits saved so much headache this year).
  • 17/64" for 1/4-20 clearance holes

Another huge game changer for us was when I purchased colour coded Allen Keys in 2020. We use 3 sizes primarily, with a few generic sets of Allen Keys for when you need that one random size.

  • Red - 5/32"
  • Blue - 9/64"
  • Gold - 1/8"

5/32 and 1/8 for 1/4-20 and 10-32 respectively. The 9/64 is specifically for the 8-32 socket head bolts used in VersaPlanetaries.

2 Likes
#11

Yes! And you can deal with most bolt/nut combinations with these two tools:

While I certainly would want more tools than this on the robot cart, keeping the number of tools required down makes finding them that much easier, as well.

And OBTW, 5/32" allen is the key to for most fire “crash” doors, which is why there’s one on my keyring.

When 3946 looked to standardize/reduce, we started first by inventorying the things we absolutely HAD to have - e.g. #10-32 bolts for mounting motors, then we looked to see if we could get rid of #8 and #12. As I recall, we mostly only used #8 for VP gearboxes, and ditched #12 completely. We needed 1/4-20 for mounting gearboxes, then we eliminated 5/16, and so forth.

#12

Defaults

  • #10-32 Socket and Flat Head (countersunk), with a few short (1/2") button heads.
  • Default to jam lock nuts most of the time, but we do have a bunch of regular lock nuts as well, plus normal hex nuts, and square nuts, for specific applications.
  • 3/16" Multi-grip rivets aluminum body, steel mandril. Dome and countersunk.
  • 13/64" drill bit for both #10 clearance and 3/16" rivet holes, 13/64" is an easier size to get in hex impact ready bits so we can easily use them in our impact drivers, drill extensions, etc. Used for drilling out 3/16" rivets as well.
  • CNC hole size is normally 0.2" for #10 and 3/16" rivets because it’s easy and close enough.

1/4-20

  • Used mostly for placers where we have a 1/4" ID tube as a standoff, so these bolt thru the standoff. Also used in our star nuts (tube connecting nuts).
  • Button and Flathead when possible so they have the same driver as #10-32, but sockets are fine when we need them. Also, a few 7/16" hex head bolts as well.
  • We also have some 1/4-20 flange head hex bolts that have a 3/8" hex head that we use sometimes.

5/16-18

  • Always button head or flat head so they have the same driver as the 1/4-20 socket head bolts.
  • Rarely do we use nuts with these, they are almost always used to go into the tapped end of a shaft/standoff (1/4" ID tube stock taps nicely to 5/16-18).

specialty stuff

  • there always ends up being some #4-40s (socket when possible) and #8-32 (button/flathead when possible) on the robot for various COTS things or places where a #10 won’t fit.
  • I will go to great lengths to avoid #6 bolts on the robot.
  • 3/8" Shoulder bolts, have a 5/16-18 thread and use the same driver as a 1/4-20 socket head bolt (3/16")

My general goal is to limit the tools needed on the robot to 3/16", 5/32", 1/8", 3/32" allen wrenches, and 7/16" and 3/8" wrenches.

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#13

What are you using countersunk screws on?

#14

Oh, yeah, don’t forget the evil breakers with the 1/4"-28 studs ;-(

I’ll have to get us some button 1/4"-20!

1 Like
#15

Nothing about button heads makes your life easier, I try to avoid them as much as possible.

1 Like
#16

Anything that needs the hardware to be flush, we countersink into 1/4" polycarb often.

1/4-28" is also the size for standard 3/4" bore pneumatic cylinder rod ends, so those nuts are good to have around for those too.

2 Likes
#17

8-32 and 1/4-20 depending on application

#18

I have a half dozen 1/4"-28 nuts on a zip tie, with a tag, in the electrical box next to the spare breaker… I should probably color code them :wink:

Yeah, all of the air cylinders seem to have fine threads on them.

1 Like
#19

10-32 for just about everything, standard socket head for most but a few button heads for where required.

One thing we do is use flanged Nylock nuts. You can place them in a box end wrench and use that to attach a nut inside a tube, under a flange or other tight location. A dab of museum wax and it doesn’t fall out.

4 Likes
#20

That’s a good thought on the flange nuts! I use them but I hadn’t thought of them in a FRC context!