Re: Use of pop-rivets?
 

They were really thin lexan ones on the base--they weren't secured solely with rivets. Rivets simply helped in holding down the middle.

Re: Use of pop-rivets?
 

Wanna race?? You unbolt and rebolt a screw, while I drill and re-pop a rivet...we will see who wins

Seriously though, rivets are very easy to remove/replace.

-Brando

Re: Use of pop-rivets?
 

I've heard this tossed around forever, and yes, drilling out a rivet and reriveting with a drill is fast... compared to a bolt with hand tools.

When the bolt is allowed to be removed with a drill (we have have ballpoint hex bits in nearly every size, along with a couple handrills with clutches, and a 6", 12", 18" and 24" extension... Not to mention 90% of the bolts on the bot use the exact same hex/wrench size), it gets a lot more even. I'd almost even lean towards a bolt winning; we can remove bolts in obscure buried places where no rivet could be drilled out.

That being said, I LOVE rivets. I just wanted to throw the counterargument out there.

I feel there is no right method and right answer, it's all about using the appropriate item in the appropriate place.

Re: Use of pop-rivets?
 

Take a look at 1501 from especially this year and you'll see the great use of rivets.

We use them for tread mostly. We also find them very useful when you want to attach something at the edge of the robot dimensions.

I also see rivets very often in every day places especially on the nyc subway, they are everywhere.

Re: Use of pop-rivets?
 

We used 3/16" and !/8" pop rivets extensively on major frame components this year. The frame was put together first with bolts to get the alignment just right, then we replaced each bolt with a rivet. We also used washers to give the rivets some extra holding power.

We also used aluminum bolts with standoffs for the drive modules.

We never had any problem with rivets, and they are quite easy to drill out and replace if the need should arise.

Re: Use of pop-rivets?
 

It depends on the robot design. It's not a trademark design item for us like it is for some teams, but on robots involving sheet metal (mainly 2007 and 2010 for us), there will be lots of rivets.

Re: Use of pop-rivets?
 

In the past 6 years Team 1501 has used over 10,000 rivets.
Last years robot had over 2000 rivets :ahh:
To say we know rivets would be an understatement.
We use a method called Monocoque (french for "One Skin"). Most of our robots do NOT hanve an internal structure. It is all bent aluminum. We use mostly .040" sheets. We have used T6 aluminum before also.
Anyone want to learn Monocoque? If so, e-mail me and I will get you a CD on how to do it.

Re: Use of pop-rivets?
 

We've used a mix of bolts (mainly 1/4-20 with a few 3/8-16 for axles) and pop-rivets in the past with decent success. 2009 was probably our most riveted robot, where we used rivets to construct most of our upper structure.

If we ever manage to get a pneumatic rivet gun we'll probably switch almost exclusively to rivets.

Re: Use of pop-rivets?
 

A bit off topic, but does anybody know a good supplier for aluminum bolts? Mcmaster is the only place that sells them that I can find, but they are almost 50cents a bolt and only offer a few sizes. Just by using them on our wheels this year, they save more weight than you might think. Thanks!

Re: Use of pop-rivets?
 

your local hardware store should have what you need... we used home depot or lowes for all of that

Re: Use of pop-rivets?
 

1756 used a lot of them this year for our paneling. They were a pain, though. I didn't like them because they didn't hold very well, and we seemed to be replacing them frequently. They were more convenient than metal rivets most of the time.

Re: Use of pop-rivets?
 

This year we used long heavy-duty ones to attach our pivot plates (crab drive) and do some non-structural work on our kicker. We've grown away from using them for wheel treads in favor of Plactions. Mostly we're not shy about using them when it fits, but we don't go crazy with it.

I haven't found a really solid supplier. Home Depot's got some, Grainger's got a few (though cheap is probably not the word for them).

Re: Use of pop-rivets?
 

Does anyone know of a good source for prefabricated aluminum L brackets and gussets drilled out for a 3/16" rivet? Sure we can continue to make them ourselves and, I guess with a jig, it would go pretty fast. If they were off the shelf somewhere though that would be temping.

Re: Use of pop-rivets?
 

A bit off topic, but does anybody know a good supplier for aluminum bolts? Mcmaster is the only place that sells them that I can find, but they are almost 50cents a bolt and only offer a few sizes. Just by using them on our wheels this year, they save more weight than you might think. Thanks!

Mcmaster has a good supply of 1/4" 20 hex bolts that are not unreasonable. Lengths range from 1/2" to at least 4" and you can get longer but they won't be fully threaded. Once you go over that size they get a bit pricey, but 1/4" is plenty big for most fastening applications. That's our standard size bolt.

Re: Use of pop-rivets?
 

i don't mean to sound critical but why would you want to use an aluminum bolt?
Aluminum isn't terribly good in shear....

Why not just drop down to a smaller size bolt if you want to reduce weight? #10 bolts are just a little over 1/2 the weight of 1/4 bolt... aluminum bolts in the same sizes would be about 33% of the weight of steel....but would have substantially less strength than the #10 steel bolts

We rarely use an 1/4 X 20 bolts on our robot... the biggest size we use is 10-24..

compare the weight of a 1/4 -20 bolt and a 10-24 bolt... you might find that that the 10-24 is a better alternative.

Compare the Clamp load of a 1/4# grade 8 bolt to a #10 grade 8 bolt and you will find that the #10 has about the 1550 lbs of clamp load and and a dry assembly torque of nearly 60 in lbs...
!/4" grade 8 bolts have the same clamp load and a dry assembly torque of a little over twice that..(140 in lbs)... if you go to #10 - 32 bolts you go up to 1800 lbs in clamp load and go to nearly 70 in lbs in dry torque...


Our team uses a number of different types of fasteners... we are gradually changing over to more blind rivet applications as we transition away from weldments to sheet metal construction.

The key to the use of fasteners, in my opinion, is two fold.

One ... use the right one for the job....
Two ... try to limit the types of bolted fasteners (IE try to standardize on your robot...)

To those that are concerned with speed of removal and replacement... either powered or unpowered...

Most of the time...you only have to have access to ONE side of a connection to place or remove a blind (pop) rivet.... any bolt will require access to the other side...to remove the nut...
Of course the easier method would be to install a screw...but this requires an initial drilling and tapping operation...screws are always the easiest fasteners to remove and replace ....

I will happily race anyone to remove and replace 10 bolts vs 10 rivets...
Rivets will win hands down...and always leave a consistent torque application...

There are MANY different types of blind rivets... look into the types... review your options...
do the homework...


i have mentioned this before but it bears repeating...
Do you know what they call 1.5 million rivets flying in formation?



A Boeing 747


:)