Attaching sheet metal to roll cage tubes

[parsonsj]

Guys, I'm working on my front inner fender sheetmetal. I'm wondering if anybody has any good ideas for attaching sheetmetal (.060 5052 aluminum) to roll cage tubing. I'd like to avoid welding tabs (hard area to reach, plus the tube is 4130 so I only weld it when I absolutely have to). The tube is .090, so drilling and tapping probably won't work.

I thought about Adel clamps, but I can't find a source that big (1.75). I found some slick aluminum bolt-on stuff in the Longacre catalog, but they are $20 apiece.

Sheet metal screws? Any other ideas?

thanks!
jp

[astroracer]

Riv-nuts would be a good option John. They stand a little proud of the tube surface so you won't have any rubbing/squeaking issues. A teflon washer could be used also to further isolate the aluminum panel.
This site has a lot of neat aircraft stuff that may interest you...
http://www.wicksaircraft.com/catalog...hp/subid=2108/
I have been kicking around the idea of using a panel adhesive like Fusor to attach new inner wheel tubs to outer sheet metal. This may work in your case also it just depends on how removable you want the panels to be.
Mark

[parsonsj]

Mark,
I definitely want to be able to remove the panel. Dennis Linson introduced me to rivet nuts a year or so ago, and I like and use them a lot.

But you have to drill a big hole which is why I wasn't thinking of them in this case. I'll have to check what size hole an 8-24 rivet nut requires ...

I definitely want to be able to remove the panel.

thanks,
jp

[astroracer]

The above link takes you right to the rivnut section. A #8-32 rivnut requires a #2 drill bit. (.221-.226 dia.) Not that big really...
Mark

[68LSS1]

John, call Goodridge Inc., Torrance, CA, 310/533-1924 on the clamps. Adel clamps are available to like 10" or 12" that I've used on aircraft. If that doesn't work or their prices are high, let me know and I'll get a price through my work. Another option would be to rivet tabs to the tube using CherryMax rivets. They are a solid, sealed pull type rivet similar to a pop but a hundred times stronger. #30 (.128) would be ideal but depending on support needed a #40 (.098) might work. They can be pulled with a standard manual gun. They are a little bit of a pain to remove. Easist way is to grind the steel locking collar, centerpunch the stem out out and then drill like a regular rivet. They are pretty weather proof as is but can be installed wet with sealer to be 100% waterproof. You can get the rivets in various lengths and even countersunk. Here's a little info on the rivets. We pretty much use them everywhere on a aircraft that you don't have or can't get access to the backside to buck a solid rivet.


Edit for here's a pdf of everything you need to know about CherryMax rivets.

[parsonsj]

Brian,

That is damned useful information. Thanks. I think I'll rivet (or weld to the non-4130 steel pieces) bases for those quick eject fastener systems that Moroso and others make.

Now I need to understand just what I need to order to put all that together.

Any idea where I could get a few hundred CherryMax rivets?

Anybody use those quick eject 1/4 turn fastener systems? What all do I need to get?

jp

[68LSS1]

You can get them from Aircraft Spruce or Skybolt. Forgot ATS. Do a Google search for CherryMax rivets and I'm sure you'll find plenty from any a/c supply store. Probably go to the maintenance facility at the local airport and get lucky. I'll check my toolbox at work tonight and see if I have a extra grip gage (used to determine length needed on unknown thickness material). The basic part number is CR3212 for countersunk, CR3213 for universal head (round), CR3242 for 1x oversize countersunk and CR3243 for 1x oversize universal head. Then the rivet diameter is added and then length. So a CR3212-4-6 is a .126 diameter countersunk rivet with a grip range of .313-.375. The diameter is a number like -4 which is .126 or -5 which is .157.
As far as the fasteners are you going with Dzus type or something similar? Dzus have the spring loaded screw that fits into a receptacle. You can get them by screw size (common or phillips) such as #6 or #8, and have to order them by length also after determining how much material it will be "through". The receptacles are the same. If you screw up the length it will be hard to install (or won't) or won't be flush. You can shim to get a perfect fit but most the time it's not necessary. Aircraft suply stores are your best bet for these also. At least they usually are for me. Here's a little info on Dzus or Hartwell Dzus. Keep in mind that these are usually riveted in (the receptacle) with two solid rivets (#40). Then there is the kind that you may be talking about that catch a wire suspended between the two mouinting rivets like here. Well speaking of work, I need to go get ready. Hopefully I've helped you some and haven't confused you too much. Some of it is sort of hard to describe.

[parsonsj]

Brian,

Good info. I downloaded the Hartwell brochure. I'll call them later, I'm sure.

I have an Aircraft Spruce catalog at home, so I can get the stuff I need from them.

thanks!
jp

[Damn True]

Just found this one. How did pulling those Cherrymax rivets go? Fun huh?

The Cherrymax is really more of a shear-load rivet. For your underhood tin a Cherry-N or Cherry-Q would have been more than adequate.







Does anyone have any experience with both riv-nuts and nutserts? Which offers the better resistance to pull-out or twist-out?

[parsonsj]

Man, that was a looong time ago.

I actually used 10-24 rivet-nuts on one side. On the other, I just drilled and tapped the tubes directly. I've had the panels on and off several times. No issues either way so far.

jp

[68LSS1]

Just found this one.

You might need to seek some help if your just finding 4 year old threads.

I'm just saying.....

[Damn True]

The point is to ask a question in an existing thread on a topic rather than create new threads covering the same topic.

[68LSS1]

DT-I was just messing with ya'.
John, in case I never thanked you I appreciate the photos of the car.

[parsonsj]

John, in case I never thanked you I appreciate the photos of the car.

Brian, no worries. Hope they helped.

jp

[Jim Nilsen]

Hey John, another alterative that hasn't been mentioned but works very well is the nylon pieces that work like the moly's you use in drywall. Once the nylon piece is in the hole and you put the sheetmetal screw in it spreads out the back and it will never come out. They really do work more than well enough to hold an inner fender on and nylon and stainless screws are not that expensive and non corrosive . You can find these used on headlight buckets on some cars.

I even have used a nylon buttonhead type fastener that you just push it in the hole and push the center in and it holds great and when you want to remove the panel you just pull the center back and the fastener comes right out. You can use them over and over again. I can post a pic of one if you like but I would think you have seen them before and just didn't realize it when you saw them. In fact they are used on a few GM cars for around the radiator shrowds or the aircleaner setups. You would find them in the GM general parts fastener catalog and they can be relatively cheap if you can get them from the General most of the time.

I am going to be doing the same kind of deal when I get to inner fenders, so it will be interesting to see what you decide.

Just a thought

[Jim Nilsen]

I was contemplating this some more and had the thought that you could glue on a stud with one of the new bonding agents available and it would eliminate any holes that might weaken the tubing.

All it takes after that is a nice little acorn nut to finish it off.

[parsonsj]

Jim,

I've had my solution in service for nearly 4 years now. I used rivet-nuts on one side, and just tapped threads on the other. Both solutions seem to be working fine, and I've R&R'ed it all a few times without issue.

jp

[hotrdblder]

john, any pics of this?

[mebuildit]

Hi guys/gals,now this is my first offical post, I'd like to recommend making something like a key hole and have the panel slide onto a stud or clip. That way there is no drilling, no welding and is very simple.
Just my .02¢ since I'm the new guy.
Greg