I’m starting a new team this year, and I’m not sure which/ how many nuts and bolts to order. Does anyone have rough numbers for how many would be a good idea to purchase initially?
all of them
It depends honestly how you want to build a robot. If you plan on using rivets, it’ll be a lot more. If it’s nuts and bolts, I can’t give an exact count cause it drastically depends on the robot, but I’d say a minimum of like 500 10-32 of various sizes and like 200 1/4-20 of various sizes. since you would also likely need to prototype. These are probably conservative numbers
And if you’re using 10-32s way more 5/32 Allen wrenches than you think you need.
Also, buy nylock nuts, in an amount over how many bolts you bought.
3/16 rivets fit in 10-32 holes and you can use the same drill, so that really helps too. Buy a lot of those. (About as many as bolts)
Probably a joke, but awful advice.
Teams should standardize their fasteners to specific sizes and head types. For example, commonly you will want to try to use socket head cap screws of sizes 8-32 and 10-32. Some teams also use 10-24.
For other applications, teams use 1/4-20 socket head screws, and for some axles also use 3/8" bolts. It really depends on your application.
Other common fasteners also include 3/16" rivets. Can’t emphasize enough how great rivets are.
Try to limit your use of 1/4-20 bolts as the cost and weight can add up.
There’s nothing worse than reaching into the tool box and pulling out a 10-24 mixed in with the 10-32s. Make sure if you buy both to separate them a lot.
You mean "it’ll be a lot less ". Since the rivets are taking the place of the bolts, right?
Like others are saying, organize all of your nuts and bolts and try and keep them in the bags or boxes they come in. It helps rather than having a big bucket labeled “bolts” and then you’re digging for 10 hours trying to find the right fastener. Organization is probably more important than actually having a lot of nuts and bolts
Here’s a good thread from years back to take a look at when deciding what fasteners to use: https://www.chiefdelphi.com/t/10-32-or-10-24/134250/46
No, cause if you used a nut and bolt to do something, you’d need multiple rivets and a gusset to achieve the same strength. Plus, you can’t undo a rivet so if you need to remove one, you need to replace it with a fresh one. Oh, and if you choose to do a lot of rivets, buy a pneumatic rivet gun
Okay. I misunderstood your meaning. I thought that your comment was about bolts.
Yes. it does take a lot of rivets. Our three previous robots have a consideral number of rivets (we estimated that our Powerup robot has in excess of 250).
And, YES to the pneumatic rivet gun. Although using a manual rivet gun did increase the average forearm strength of our mechanical team.
We also make new members manually install 10 rivets before they are allowed to touch the pneumatic gun.
Purchase a couple dozen 4-40s and 6-32s for electronics/small components. You won’t need many, but you’ll be glad you had some on hand when you do.
Standardize around either 10-32 or 1/4-20 hardware as much as you can. 10-32s are smaller/cheaper/lighter and good for most of the loads experienced by FRC robots. 1/4-20s work natively with 80/20, thunderhex, and churros. So it just depends on what hardware you plan on using. Buy whichever you standardize around in a variety of lengths ranging from 1/2" to 3". For the longer screws, ones that aren’t entirely threaded are stronger and cheaper. But fully threaded machine screws can always be cut down to the length required.
Buy associated lock nuts for each screw size you purchased.
3/16" rivets are also great if you plan on using a lot of extruded aluminum tubing and/or thin sheet metal.
some people have already said this but I want to stress that you should not buy very many different sizes of nuts/bolts and make sure you keep the different types very separate. This year we decided to get almost all new nuts and bolts because of how mixed and difficult to deal with it became
Whatever you are buying, it is much less expensive if you buy in bulk boxes. Typically, these contain 100 pieces.
The boxes are also a good way to keep the different fasteners organized. Otherwise, these parts organizer boxes are very good. The dividers prevent the small parts from going into adjacent bins. They also stack and can latch on to each other and some of the tool boxes from DeWalt.
Not to re-hash what everyone else has said, but standardize as much as you can around a #10 type bolt (10-32 is great), have assorted 1/4-20, 6-32, 8-32 on hand as well.
The tough part from my experience is not having fasteners that are long enough in some scenarios. So you may consider the types of materials you’ll be working with - 1" and 2" thick extrusions - and order 1/2" - 1" longer to get through hubs and other items that often bolt to those things.
When in need, McMaster has just about everything you could possibly want. You pay a bit more but for us it comes next day ground, can’t complain about that during build season.
Pick a size, try to standardize on it (we use 10-32, others use 8-32, 10-24, or 1/4-20). We then order hundreds of a few sizes we use a lot such as 1/4, 1/2, 3/4 and 1in lengths, and 600ish PEM nuts, 300 nylocks, and so on.
If you have a Tractor Supply nearby it can be very cost-effective to standardize on 1/4-20 and buy their fasteners by the pound. It’s quite inexpensive and they’re decent fasteners.
Don’t buy now. Design your robot, spec your fasteners, order from McMaster or elsewhere, save the extras.
I would disagree with this, especially for a new team. It’s awfully hard to prototype if you don’t have some fasteners on hand before. Additionally, a rookie team’s design process isn’t likely to be as streamlined, especially when it comes to finer details like fasteners.
If you don’t have a good rivet gun, please don’t force your students to rivet. I remember the first time my team started to use rivets, and the gun kept jamming, and the thing had a very un-ergonomic grip. More hassle than it was worth. Still skews my opinion on rivets, but they definitely have their benefits.
Standardization is the key in an ideal world you want only 1 hex key, and 1 wrench to assemble/disassemble your robot. This is next to impossible to achieve. Use 10-32 as much as possible. 1/4-20 if you are holding together critical structures. Then go onto mcmaster and order a bunch of the tools you need specifically for those fasteners. Can’t remember off the top of my head which hex keys, and which wrenches, but that is what google is for.
As for qty buy bulk. Far cheaper and easier to buy 500 10-32 bolts from fastenal than it is to run out of bolts and go to the hardware store.
200x 10-32 x 1/2 (sheet metal to sheet metal)
200x 10-32 x 1-1/2 (sheet metal to tube)
200x 10-3 x 2-1/2 (tube to tube)
200x 1/4-20 x 1-1/2 (tube to sheet metal)
200x 1/4-20 x 2-1/2 (tube to tube)
Try to use a Kanban System. if a tub drops below 25 nuts/bolts replenish that stock.
Better yet, buy one of these and make riveting fun! - https://www.harborfreight.com/3-16-inch-air-hydraulic-riveter-93458.html
I’ve had students that were afraid to pickup a tool assembling things with these by the end of the night. If you plan to use more than a handful of rivets, it’s well worth it. Air compressor required, which you’ll need eventually anyway.