15-11-2014 00:55

75vs1885

Re: pic: new shoes

on the original wheel , did you only rivet once? When we try the rivets are not reliable. We know why, but have a difficult time mastering riveting!!

15-11-2014 00:59

who716

Re: pic: new shoes

we took our andymark 6 in wheels on concrete for a day of presentations and by the end of the day brand new wheels were completely flat like yours

15-11-2014 01:00

BJT

Re: pic: new shoes

yes, we use plenty of rivets. never had any problems.

15-11-2014 01:02

BJT

Re: pic: new shoes

It was a parade that flattened these.

15-11-2014 10:05

snoman

Re: pic: new shoes

if you are not using a pneumatic rivet gun i suggest that you get one. they seem to tighten it up a lot more 70 or 80 bucks good investment use steel rivets to

15-11-2014 13:22

Chris is me

Re: pic: new shoes

Large head rivets work really well for securing tread. Otherwise, just be sure you're putting rivets in the "dip" of the tread as much as you can and use all of them. Going to steel isn't really much help and it just makes changing tread a ton harder. You just need the rivets to last as long as the tread.

15-11-2014 14:50

Chadfrom308

Re: pic: new shoes

We used a little bit of glue too. Ours were on there pretty tight. Steel rivets helps as opposed to aluminium. We had an all aluminum rivet robot last year and we ended up popping the rivets left and right (especially in high impact/stress areas)(at least the rivets broke and not the frame itself).

15-11-2014 22:10

75vs1885

Re: pic: new shoes

I guess its a double whammy for me, lol, we use a hand rivet gun and aluminum rivets!!
We have a pneumatic rivet gun and i tried using it today but I need to practice.

16-11-2014 00:52

BJT

Re: pic: new shoes

we use a pneumatic rivet gun now, but have also had success with a good hand riveter. we drill through the tread and the wheel in one of the "dips" in the tread. when we rivet it by hand, I push down on the head of the gun real hard and a student runs the handle. If they get in good and tight aluminum rivets will work fine.

16-11-2014 01:16

sanddrag

Re: pic: new shoes

Once you get a pneumatic rivet puller, you'll wonder how you ever lived without it. It's hands down our best tool under $100.

16-11-2014 02:00

R.C.

Re: pic: new shoes

Under $50 actually. By far one of my favorite tools to have around the shop.

16-11-2014 11:09

Oblarg

Re: pic: new shoes

When you factor in the cost of a compressor, it's not inexpensive. Unfortunately, neither of the teams I mentor has a compressed air line in their workspace.

A good hand riveter (all-metal construction with suitably long handles) works fine, in my experience.

16-11-2014 12:20

AdamHeard

Re: pic: new shoes

If a team is doing rivets in any meaningful qty, spending a few hundred bucks for a nice riveter and small compressor is well worth it.

16-11-2014 12:27

Abhishek R

Re: pic: new shoes

We had our first experience with an air-powered riveter this past year. Especially after doing the entire prototype robot by hand, I couldn't believe how we had survived without that tool. Made things go by faster and without less stress on a few select students ^^

16-11-2014 12:46

Oblarg

Re: pic: new shoes

I think it depends on what you mean by "meaningful quantity." If you're putting together a tube-and-gusset chassis, it's not all that difficult to do your riveting by hand. It's still faster than bolting the assembly together.

If you're doing sheet metal, I can see how it would be a real pain to have to do all your rivets manually.

16-11-2014 12:49

AdamHeard

Re: pic: new shoes

We do tube and gusset for pretty much every system. We did't have a pneumatic riveter until 2011, and did hand until then.

It's certainly meaningful quantity, and it's certainly worth it. The time saved is huge.

I like to think of labor in terms of minimum wage. If the cost of a tool saves enough labor that it's "making" more than minimum wage, it's worth it (as our kids make well above minimum wage when they're out fundraising). The flipside is true too... any fabrication we do that "saves" less than minimum wage is a bad decision, and should be a COTS item.

Too many teams work themselves for below minimum wage.

16-11-2014 12:58

Oblarg

Re: pic: new shoes

Unfortunately, the reality for many teams is that time spent is not some limitlessly fungible resource where any time saved in manufacturing can be converted to money through fundraising efforts.

16-11-2014 13:07

AdamHeard

Re: pic: new shoes

Is there a law/rule against fundraising for you locally?

16-11-2014 13:17

Oblarg

Re: pic: new shoes

No, but there are practical considerations in how much time we can realistically motivate our students to spend on fundraising, how much money that fundraising will actually bring in, and when it is feasible to do fundraising activities (time saved during our twice-weekly preseason meetings is not equivalent to time spent at events outside of those meetings).

If we save some amount of time on our preseason drive chassis (say, an hour or two) by having a pneumatic riveter, there is really no feasible way we can readily turn that hour or two into money given the constraints of our team structure.

There are a lot of assumptions implicit in the utility calculation you've outlined. Those assumptions are valid in some contexts, but certainly not universally.

16-11-2014 13:21

Chris is me

Re: pic: new shoes

We bought the Harbor Freight riveter right before our 2014 season to save us time and energy... and broke it almost immediately. We ended up just getting another hand riveter and using two of those. Ate up a LOT of time in build season though - with the amount of rivets in the claw we probably consumed more than 1 build meeting total in extra time wasted.

That said, hand riveters get the job done just fine. With practice we could do things like change claw parts (drilling out at least 12-16 rivets and replacing them) in just a few minutes.

16-11-2014 13:46

75vs1885

Re: pic: new shoes

I was trying it yesterday and it wasn't working well at all, however out hose was leaking a lot so i think that was the direct cause. Once we fix/ replace the hose we can see how it works!

17-11-2014 09:51

JesseK

Re: pic: new shoes

Stephen, were you using the small yellow compressor directly or hooking it up to the wall-mounted air line? Send an email to Drake/Laverty to get a replacement host once you find the leak.

I'm not sure it's worth it to bring a compressor tank & air rivet gun to competition just for tread rivets, so we'll have to see what else we can rivet this season if the air rivet gun works so well we decide to go that route.

18-11-2014 20:56

75vs1885

Re: pic: new shoes

The small yellow one. As for competition I don't even think we can bring a compressor, if I recall properly then I saw a rule against it.

18-11-2014 22:03

orangemoore

Re: pic: new shoes

Bringing a compressor to competition is complicated. It is a black hole of debate.

18-11-2014 22:06

cgmv123

Re: pic: new shoes

There shouldn't be as much debate as there is; all the inspectors say "don't bring a non-robot compressor".

EDIT: *Ducks*

18-11-2014 22:13

Gregor

Re: pic: new shoes

Care to cite a rule?

18-11-2014 22:17

mman1506

Re: pic: new shoes

After some testing we found a large hand riveter (the style typically used for large rivets) worked better for putting nitrile on aluminium wheels than a air riveter. It allowed us to put a lot more pressure on the rivet when setting it compressing the tread around the rivet to create a secure attachment.

18-11-2014 22:33

cgmv123

Re: pic: new shoes

These aren't rules, but any rules I can cite won't apply next year anyway:

http://www.chiefdelphi.com/forums/sh...1&postcount=62
http://www.chiefdelphi.com/forums/sh...1&postcount=79
http://www.chiefdelphi.com/forums/sh...0&postcount=96
http://www.chiefdelphi.com/forums/sh...&postcount=118
http://www.chiefdelphi.com/forums/sh...&postcount=121
http://www.chiefdelphi.com/forums/sh...&postcount=123
http://www.chiefdelphi.com/forums/sh...20&postcount=4
http://www.chiefdelphi.com/forums/sh...3&postcount=15

18-11-2014 22:49

Gregor

Re: pic: new shoes

Right, they're not absolutely disallowed. A blanket statement saying "all inspectors" will ask you to remove a shop compressor isn't true. Some events will allow them, some will not.

And some events will not allow them because teams MIGHT use them to fill up their air tanks???

18-11-2014 23:18

mman1506

Re: pic: new shoes

Plug a air line into the robot's compressed air release valve and connect the other end to the riveter. Problem solved.

19-11-2014 07:56

g_sawchuk

Re: pic: new shoes

Wow, someone sure has been using those wheels. We had a demo on pavement, but we limited skid turns, so by the end, they were only a bit worn down. Then we replaced them for an off season event.

19-11-2014 17:36

Andrew Schreiber

Re: pic: new shoes

This is absolutely incorrect. There was NOT a rule in the books to forbid it. They can ask you not to run your shop compressor due to power concerns and you are absolutely not allowed to fill up your robot tanks from it. But there is NOT a rule saying it cannot be in the pits.

19-11-2014 21:39

Richard Wallace

Re: pic: new shoes

My those treads are worn. Good thing you know how to replace them, quickly.

----

Re: thread hijack to pit compressors -- at many events where I have volunteered, the people responsible for pit power want to know which teams have compressors. For example, at St. Joseph last year, we kept an inspector assigned to watch teams unloading and check for pit compressors. This was NOT motivated by suspicion that such teams might use pit compressors to fill pneumatic storage tanks before a match. It was motivated by a strong desire to keep pit power in service all the time, even if that meant juggling pit assignments so that the number of compressors on any one distribution circuit did not get too high. Fortunately, we did not need to move any teams or ask them to refrain from using pit compressors. I have been at events in past years where one or both of those things did occur.

Most of the pit compressors I have seen teams use at FRC events were rated for 15A current draw. That in itself is not much of a problem; however, many of these things draw much larger surge current when they start (I have measured up to 50A for a split-second) and THAT can push an already loaded distribution breaker past its trip point, knocking out power to a row of pits. Then the roadies have to scurry ...