Is riveting that much better?
 

For the past two seasons we've used good ol' fashioned nuts and bolts to keep the bot together. After the second regional, our bot got pretty roughed up and nuts start coming off or becoming loose.
I was wondering how many teams have been using rivets to keep their bot together and if so, did you use them for the whole bot? Did they perform well?
Also, is it really final when you fasten the bot together with rivets or is it relatively easy to remove them if mistakes were made or adjustments are needed?

Re: Is riveting that much better?
 

We haven't used rivets, but a quick search of the forums for "rivet frame" comes up with many related threads, such as this one http://www.chiefdelphi.com/forums/sh...ht=rivet+frame

I can say that welding the kitbot frame significantly increases frame stiffness relative to bolts, and saves probably one or two pounds of bolts in the process. Rivets offer a signficant weight savings, too, I understand, and in this game saving a few ounces can make a big difference.

Jason

Re: Is riveting that much better?
 

We've riveted large numbers of joints since 2007 and are very happy with how they've held up in competition. We use 1/4" aluminum or steel rivets as necessary. Steel rivets are much harder to drill out, so we use them sparingly, and otherwise avoid using rivets at points where whole mechanisms couple to the robot so that we can more easily remove them should that need arise.

1/4" rivets require a special tool that is about $150. Ours is called the Big Daddy - by its manufacturer -- and we bought it at a local supplier of hardware and tools. You can also order them through McMaster-Carr or similar, I'm sure.

Re: Is riveting that much better?
 

The past few years we've used a lot of rivets, mostly on the mechanism, but our 2008 chassis was riveted together (fiberglass channel and sheet aluminum). We prefer smaller rivets, mostly 5/32", we also use some 1/16" and 3/16" rivets where appropriate. Sometimes the rivets get loose...that generally means the joint was not designed properly.

See if you can find pictures of some past 1501 robots :)

Re: Is riveting that much better?
 

217 and 148 are my favorites for riveting. Search CD-Media for their bots.

-RC

Re: Is riveting that much better?
 

In one word to answer your question.... yes. If you have specific questions, feel free to send me a private message. The past examples of different teams have led me to believe that rivets do a great job; as well as led me to use rivets for my teams.

Re: Is riveting that much better?
 

Our basic frame is welded, but we use a lot of rivets for attachments and lexan. They are easy to drill out and remove when needed and are great for quick fixes. The mechanical team has a large assortment of diameters and lengths as well as aluminum and steel.

Re: Is riveting that much better?
 

In 2008, our grabber completely snapped off (hit a wall head on) and were scheduled for a back to back match. A hand full of rivets, hand drill, and a manual rivet gun; we had the grabber back together before the staff had the field reset:cool:

Re: Is riveting that much better?
 

I'm guessing we are mostly talking about steel and aluminum 'pop-rivets'.

Does anyone use solid rivets ? They are used on with a riveting tool that vibration hammers the rivet against a bucking bar.

If you are riding down the road look at the side of a common tractor trailer made of aluminum structural framing. A zillion of the rivets. Used on aircraft too !!

Re: Is riveting that much better?
 

177 has been known to buck solid rivets in our robots. We have the full aircraft builder's set up in our shop with pnuematic hammer, a variety of bucking bars, and plenty of kleckos.

Former mentors on our team built their own aircraft and taught us how to dimpel the sheet metal and everything. We usually only use this in applications were we need higher shear strength or the rivet needs to be counter sunk, or we make a monocoque structure out of sheetmetal

I believe 1501 Thrust uses some solid rivets in their robots as well because they build their robots almost exclusively in a monocoque aircraft fashion.

Re: Is riveting that much better?
 

Any recommendations on pneumatic hammers ? Bars ?

We have done projects where it would have been really nice to do it that way but we didn't have the tools or knowledge at the time.

Re: Is riveting that much better?
 

I'll take a look at what we have this weekend and let you know.

Re: Is riveting that much better?
 

Instead of "Is riveting that much better?", a better question would be "what are the pros and cons of riveting?" Just like everything else in this world, there are advantages and disadvantages. I'll post some of each below, but I'm sure there are more that other people can think of.

(btw, I'm referring to pop rivets here)

Pros:
- light weight. We once weight all of our fasteners on a robot and it came out to nearly 20 lb. An aluminum pop rivet weights about one tenth of the steel nut/bolt combo it replaces, so you can save 5 lb pretty easily with good use of rivets.

- Fast and easy removal and replacement. You don't need to track down the 7/16" wrenches and unscrew a bunch of nuts. Grab a drill and the proper drill bit, and two seconds worth of drilling will remove each rivet. You can easily remove 10 rivets in less than a minute, and that includes searching for the drill. Likewise for attachment. It takes about 10 seconds to load a rivet into the gun and do the fastening - no need to figure out how to hold a nut still in a hard to reach location.

- thread locker not necessary

Cons:
- Not as strong as a nut and bolt. They're much lighter and sometimes rely on a bit of friction to do their thing. If it needs to bear a lot of load, you should probably stick with the nut and bolt.

- Special equipment necessary. You have to buy a rivet gun and make sure you have the right drill bit to remove the rivet if you need to.

- Drilling out rivets can sometimes leave rivet remnants in place where you may not want them (like inside of tubes). Usually not a big deal, but something you might want to think about.

I'm sure other people can expand on this, but this should at least get you started.

Re: Is riveting that much better?
 

....or design the assembly so it can use several rivets. Usually the stuff we rivet is made with sheet aluminum brackets riveted to aluminum tubing.

Re: Is riveting that much better?
 

That was my thought too. You say they weigh 1/10th of a steel bolt/nut combo. So throw 5 of them on to replace a bolt/nut and you are still under.

Re: Is riveting that much better?
 

If you're trying to join two pieces of 1" aluminum at a 90 degree angle, you may not be able to do that (you would have a 1" x 1" overlap). You could use a 90 degree plate to do the joint and then use lots of rivets, but I would argue that a nut and bolt would be simpler and lighter at that point. I guess my point is, do whatever is simplest (KISS).

Re: Is riveting that much better?
 

Glue it, screw it, bolt it, rivet it, weld it. If the design is flawed it will fail.

Re: Is riveting that much better?
 

Case in point, for any large pieces of sheet metal (like many of the bots I have seen riveted) more rivets is probably better but I suppose its easier sometimes to bolt things like that together as sheet metal gussets would make it non KISS.

Re: Is riveting that much better?
 

Last year we made this super awesome looking shooter guard for our turret wheel and it took us well into the morning, needless to say we forgot about rivets...

If you can't get a screw in there make sure not to forget about the rivets.

Re: Is riveting that much better?
 

Yes, yes it is.

For one thing, as awesome as welding is you are usually going to have two problems:
1) Frame distortion- Every frame I have designed that has been welded has warped to some degree (especially aluminium), this is not a happy thing to deal with (wheel contact, conveyor alignment... ).
2) Skill- My team was lucky to have a veteran welder around, but I have seen what happens when a new student tries to weld aluminium. It becomes more like modern art, and less like robot frame :rolleyes:.

Bolts lose in the weight and remaining tight categories.

Rivets are light, easily installed and uninstalled, and create pretty solid joints when done correctly. I think every FRC robot has at least one application where rivets would be the most useful of all fasteners.

Re: Is riveting that much better?
 

im glad to see 1501 is known when it comes to riveting :)
our team has used over 10,000 rivets on our robots so far, almost 2000 in some robots. They are made out of a monocoque design, which is what aircraft use. solely sheetmetal and rivets, providing a strong structure. i think youll enjoy some photos of our bots.

www.huntingtonrobotics.org

all we use are hand rivet guns and a pneumatic rivet gun (used rarely)... i have spent all nighters riveting the bots together. but it creates an amazing end product. if you would like more info, pm me and i can get it to you. and yes we do make errors, but you can just use the same drill bit you used to make the original whole and drill the rivet back out. almost as if it were never there.

and klekos are a neccessity when building with this many rivets :rolleyes:

Re: Is riveting that much better?
 

Samir,

The link doesn't seem to be working.

-RC

Re: Is riveting that much better?
 

lol whoops... thanks squirrel! i got a little ahead of myself... i corrected the link

Re: Is riveting that much better?
 

Since I do not have much experience with rivets, care to explain what the rather large things between the already finished rivets are?

http://www.flickr.com/photos/teamthr...7614958581531/

Are they a tool for putting on solid rivets or something?

Re: Is riveting that much better?
 

They are clamps, more or less.

Re: Is riveting that much better?
 

those are called Clekos, they serve as a quick insert stand in for a rivet to get things aligned.
Think of them as vice grips for sheet metal joints, they hold everything in line when you start putting in the real rivets.

Re: Is riveting that much better?
 

So, they clamp it by slipping through the holes so other rivet holes will line up?

Re: Is riveting that much better?
 

effectively a stand in rivet, yes

Re: Is riveting that much better?
 

long answer: there are pros and cons of each.

short answer: YES

While I still use bolts for super high shear areas, 90 percent of the fasteners we used last year were rivets. Our entire robot was essentially 1/4" aluminum rivets, 1x1x1/16 aluminum tubing, and 4"x4" aluminum triangles for corner connections. We never had a rivet fail. Removal is easy as pie too, just drill through. Hole enlargement was minimal in my experience since the center of the rivet kept the bit straight.

I think someone said earlier that a team could dissassemble and reassemble a robot faster using rivets than bolts. I have to agree, you just have to drill through and re-rivet. I also hate having to tighten loose nuts so riveting is definitely my favorite.

-Vivek

EDIT: With a good square, you can get perfect 90 degree angles without machined corner braces. We just cut them on a miter saw and clamped everything down to a work bench and lined it up with a square. Make sure your holes are aligned though.

EDIT2: We probably saved a few pounds by using rivets too. They are SOO much easier to maintain. Sorry about the edits, I just really love rivets. :)

Re: Is riveting that much better?
 

like most people said rivets are nice for more permanent uses. you have to drill them out if you need to undo the fastening.

i would suggest staying with the nut and bolt, but use locking washers or loctite. Or use the nuts with the nylon in the tips.

Re: Is riveting that much better?
 

just a heads up on the klekos:

they can be purchased from an aircraft supply store, if you want i could post the link (i would have to look it up quickly)

Basically, to drill all the holes we use templates. we drill one hole, put the drill template on top (the templates are just like ruler with holes drilled various distances from each other, commonly use 3/4-1 inch spacing) we kleko it in (kleko=temporary rivet) and then we drill the opposite side hole in the template, kleko that in, and then drill in between.

short quick description: a kleko is a temporary rivet that is inserted with a plier like specialty tool. it holds things together so that you can align before you actually put rivets in.

(you want to space klekos approximately 3-4 holes apart on straight lines, or about every other hole on complex parts like the curve in the picture mentioned) 50 klekos will do most teams well, i believe we have about 200 or so:D

Re: Is riveting that much better?
 

If you use nuts and bolts, use nuts with a nylon insert so they lock in place.

Also, last fall we used some machine screws that had a nylon segment incorporated into the threads, which made them locking, but not permanent.

Re: Is riveting that much better?
 

For clarity, you should already have seen what a klecko is (see some previous posts). A bucking bar is a relatively heavy bar of metal, maybe the size of a hammer head, with a dimple in one end made to fit the head of a solid rivet. You hold the rivet (which looks like a short nail with no point) in place with it, and whack the other end with the pneumatic hammer. The inertia of the bar holds the rivet in place so the hammer can flatten the other end. They also make bucking bars for the end-to-be-flattened, one uses it kind of like a chisel with a manual hammer. A little more effort, but really low-tech and thus simple. But you need three hands: bucking bar, flattening bar, and hammer.

Very large rivets (think George Washington Bridge) are heated so they flatten more easily, with the important added benefit of shrinking when the cool, thus pulling the joint together even tighter. Small rivets (think FRC177 robot) rarely are heated.

Re: Is riveting that much better?
 

Looks like Cleko and Cleco are the most common spelling :)



(we've never used them, because we don't have any, and we don't make stuff quite as nice as 1501 does)