RIvet Nuts / RivNuts info or advice?

rayra

Expedition Leader
I'm considering pulling the trigger on this RivNut kit -
https://www.amazon.com/Astro-Pneuma...rd_wg=mDxP1&psc=1&refRID=MSHX8PWSTB557RSFZA93
- as a precursor to the fuel tank protective plate project later this year. Essneitally I want to mount a flat plate to the bottom of my frame and crossmember / support a plate under my fuel tank. The inboard edge near the driveshaft will be supported by a tubular frame support attached to the tank hangar strap mount locations. Won't be something strong enough to support a high center, more for protecting that huge expanse of poly tank from road debris, ladders and the shattered thighbones of zombie protesters.

Thinking to use cap- or pan-head bolts with either torx or allen head, want something rounded that might grind over a boulder or obstacle better, in case I do high center on something. The GMT800 fuel tanks are basically flush with the bottom of the frame, with only the transfer case shield hanging lower, in the mid-body expanse (and the driveshaft of course).

Looking for any advice on using these RivNuts, on using the tool, whatever is relevant.
 

Ducky's Dad

Explorer
Big rivnuts can take a lot of muscle, especially if you don't have a good angle, and it can be hard to get a good angle with that tool. Sometimes tough to put on extension handles (lengths of pipe) when the angle isn't good. If you use that tool, might be good to have a lift, rather than just jack stands.
 
B

BPD53

Guest
The installation tool you linked looks fine for the price.

I prefer ribbed stainless rivnuts personally. I live in an area that uses road salt for ice and snow so I need some help avoiding corrosion. Stainless rivnuts work well, but they are more difficult to drill out if you need them removed.

Always use a good drill bit when installing rivnuts. The quality of the rivnut is directly related to the quality of the hole drilled. You'll be surprised how big a hole you'll need to drill even for a 1/4-20 rivnut.

Rivnuts are best suited for flat surfaces. You mentioned a tubular frame support so it could cause an issue where the rivnut would not "seat" good. I've had 50/50 results using rivnuts in a tube.

I tell people only use a rivnut when they have too. If a bolt and nut will work I say go that route. Sometimes a rivnut is perfect though. Ive never had a rivnut spin or pull out once installed.

Be aware that the size of your rivnut tool can be a problem at times. I've got one similar to the one you are considering and it doesn't always fit where I need it too.

If you look on eBay they sell the type I prefer fairly "cheap". They are still expensive but they will do more than just rivnuts and come with a 90 degree head attachment. It fits in tighter spots and has been more useful than my manual rivnut tool.

The one I prefer is made by Fastening Systems International:
 

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BPD53

Guest
Can't remember where I got them but these have been quality rivnuts:
 

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Whatever tool you choose make sure you can easily get replacement parts like the spindle. They can break especially with tough nuts like stainless. Since this will be used in an exposed place look at closed end or blind rivet nuts. This will prevent dirt and water from migrating from the backside.
 

jgaz

Adventurer
The tools are great if there are lots to set & room to work.
Being I am a cheap bugger, Just use a wrench, screw, nut & couple washers to set them.
Said that, its always better to set these things or poprivets in one smooth action...

In my experience, this may be the best way to set the inserts if you are on your back under the vehicle. I've set dozens of the M6 and M8 size at work and have had excellent success using the above method with a Milwaukee M12 electric impact wrench. It has excellent trigger control. This feature, combined with its lower torque and a bit of experience, allows the one smooth action that really helps set inserts correctly.

If I was in the market for a tool I'd look into to the hydraulic unit BPD53 showed. I used the Huck brand pop rivet version of this design to set the 1/4” structural rivets that GM was so fond of in the 80's. It worked very well. It was expensive and cheaper alternatives weren't readily available.
 
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outback97

Adventurer
I used this setup, but I only had to set a few of them. If I had to do more I'd probably want a purpose made tool, though this did work well in a confined space.

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javajoe79

Fabricator
I use the individual drivers that require two wrenches. They use a bolt as a mandrel so any correct length or longer bolt will work if you break one. They’re also great for tight spaces. I always use the high strength ribbed rivnuts and a dab of loctite around the ribs before setting them. I also use anti seize on any fastener I thread into one. I order everything from mcmaster carr
 

rayra

Expedition Leader
Thanks for all the info. Clearance would be an issue for other projects, possibly, but not for the bottom plate. Bottom of my frame is 14" off the driveaway, just sitting on the tires. The tool in the kit appears to be 13" so I may be able to use it without even raising the vehicle.

The tubing I'm consider would be square, 1" or 3/4", but I'm not sure its wall thickness would be enough. And where it's at could just as easily be a pass-thru bolt. The way the GMT800 chassis and fuel tank is laid out, it's a nice flat(ish) plane. I'm thinking to make a sort of ladder frame out of the square tubing on the inboard side of the tank, suspended from the tank mounting points. Then the skin / plate would be on teh frame rail, a cross member at the front, the ladder frame inboard and possibly a right angle extension of the ladder frame to the vehicle frame rail, right before the upturn / rear trailing arm mount. With the tail of the plate unsupported and turned / tucked upward, following the end of the tank.

I saved a lot of large cardboard durign the holiday season, as soon as I shrug off this near-flu I'm going to get busy mocking up the plate and frame.

I'm thinking to use 5/16"-18 rivnuts / bolts and am looking for pan head boltes, allen drive I think, 'cap head' seem to stick up / down too much for where I plan to put them.

eta make that 'truss' head -
31wlP5qyLAL._AC_US218_.jpg

https://www.amazon.com/Machine-Scre...3971011,p_n_feature_two_browse-bin:2292869011


I'm having a hard time finding any ~3/16 aluminum plate for less than $400 for a 4'x8' sheet. Can't recall (or find) the measurements right now, but iirc I need something like 22"x72"+ for what I want to make and have uses for the rest.

I mostly want it as a second skin for the tank, not a true weight-bearing 'skid plate'
 
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Ducky's Dad

Explorer
I'm having a hard time finding any ~3/16 aluminum plate for less than $400 for a 4'x8' sheet.
Have you tried Industrial Metal Supply on San Fernando Road? They have bins full of scrap and cutoffs out in the shop area, sold by the pound, and you might get lucky. Might save a ton of money by finding two pieces 11x72 and just installing side by side on your fabbed frame. And they can make nice clean cuts for you on the thick stuff, not very expensive.
 

javajoe79

Fabricator
I would use flat head allens. Countersink the holes in the aluminum plate. Be sure to order rivnuts that are meant for the material thickness of your tubing.
 

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