Re: Riveting up a frame
 

We used rivets in 2005 and 2006 and those were our best robots, by far. We used 1/8" aluminum rivets with aluminum mandrels in most places, but 1/8" aluminum rivets with steel mandrels in places where we could not use a lot of rivets, but needed strength. Our entire drive base, main structure and end of arm in 2005 were riveted sheet metal. Our entire drive base, tower, and shooter frame in 2006 were riveted sheet metal.

Anyone who says the rivets are not strong enough have either not used it, or implemented the rivets improperly. Strength to weight ratio is out of this world and I will race anyone changing out a component riveted together vs. bolted together. Our riveted components can be repaired and replaced much faster with rivets than with nuts and bolts.

Using 1/4" rivets in the kit frame should prove very effective. Also remember, you want to have a mechanical fuse when it comes to collisions. We usually do not have the weight to design our components against severe crashes/mishaps, but the rivets will break in key areas in order to save components.

Re: Riveting up a frame
 

Personally, I find it alot easier to lay a bead then riveting, but to each his own.

and who cares if it works. :)

Re: Riveting up a frame
 

yeah thats correct we used rivets this year more then any previous year and we were quite happy with how it held up.

Re: Riveting up a frame
 

Re: Riveting up a frame
 

we did use rivets but it was mostly in the upper frame around the shooter and such...i dont think that we would ever use them on the driveframe...but i think that they did hold up quite well. but again you must be careful where they are place and the amount of stress.

Re: Riveting up a frame
 

177 Uses POP rivets in similar ways to what Paul said above for 217. We also use solid aircraft rivets installed with a pnuematic hammer and bucking bar in application where higher shear strength is needed or if we need the rivet to be flat headed. We have made arms capable of lifting a robot of the ground this way using aircraft construction methods. Needless to say we believe the strength is there.

A word of advice if you plan on using big diameter rivets is to get a pneumatic tool for installation. Particularly if you use a lot of them.

Just a general comment, we find a mixture of joining using welding, rivets, rivnuts, and nut/bolt fastening depending on the application gives us the best solution for the problem. Don't rule out any of these methods unless you are not properly equipped to do them.

Re: Riveting up a frame
 

Interesting discussion - good question Billfred. I'm surprised to hear the amount of success using rivets and the kitbot, especially using backing washers. Normal design practice for rivets - at least in my work experience - is to avoid tensile loading and just use them for shear loading (obviously they have some amount of tensile capability, but they aren't designed for it) Installation involves match drilling close fit holes - I would think that the kitbot standard clearance holes are nowhere near adequate to get a good interference fit after bucking or popping. Has anyone run any calcs or tested tensile load capacity?

S.P.A.M. (I can't say 'we' anymore) has used rivets very successfully on some structural components, but not the chassis. Definitely the lightweight solution if you can make it work.

Re: Riveting up a frame
 

What do you call a 747?





A million rivets flying in formation!


Back in the days when Northrop Grumman was just plain Northrop, we built the fuselage for 747s. We also installed 3/4 of those million rivets. (Actually I think it was 995,000 but at that point who's counting?)

In modern aircraft structure rivets are often used for joints that are never intended to come apart. Just walk down the F-18 line with me sometime and listen to all the rivet guns, and just why do you suppose hearing protection is required in all the assembly areas?

Used properly, rivets are a very practical fastening method, but they have to be done right to work. That means matching the rivet diameter and length to the hole, countersinking to the correct depth for flush rivets, and using the proper mandrels and riveting tools. But if it is good enough for a modern fighter aircraft if ought to be good enough for a FIRST robot.

Re: Riveting up a frame
 

We use 1/8" rivets EVERYWHERE.

See how to link here:
http://www.huntingtonrobotics.org/in...d=1&Itemid =2

Or Video here:
http://www.huntingtonrobotics.org/in...=1&key=1&hit=1

The whole frame is "ribbed" and "skinned". Just like an airplane is made. No need for welded steel. It does get "dented", but it never has "failed" on us yet. Even the wheels are riveted with bulkheads and quite strong.

Re: Riveting up a frame
 

What is this pick on chakorules day? LOL ;-). I didn't get a chance to respond to myself in that post. I meant, kitbot and rivets don't mix well because we don't normally use the kitbot frame, we make our own frame. I didn't mean it as it "reads" like we used rivets on the kitbot frame. We have never tried that to my knowledge. We always use the bolts and normally we use the kitbot to build a proto-type frame to the programming team, that's where I come in. I don't think I've ever even used the pop-rivet gun yet in three years on the team, woooo.....I am gunna get it for saying that....

Re: Riveting up a frame
 

I went on a tour of some production lines and was amazed at how many rivets were being used.

Re: Riveting up a frame
 

Nah, I didn't mean it that way. I guess my sense of humor didn't come through on that one. I guess I was trying to point out that I tried to start this very discussion about riveting KitBot frames back then but nobody seemed to take the bait at the time.

Re: Riveting up a frame
 

We have aluminum pop riveted some assemblies with excellent results.
A good design practice is to use a splice plate or gusset plate at connections between two structural members & install multiple rivets in each member.
For instance at a right angle connection between two tubes, put a triangular gusset top & bottom with 4 rivets thru the gusset plates into each tube.
This also spreads the load over a larger area of the frame tubes, reducing the likelyhood of exceeding material yield at a single concentrated point if using one rivet.
A 3/16 rivet is the same size as a #10 screw. Holes are easy to drill and they are plenty strong for anything on a FIRST robot if using multiple rivets at a joint.

1/8 rivet are great for adding small plates for limit switches etc. or reinforcing structures after it's all bolted together.