Hopefully with some reinforcement? Asking a nutsert to hold a seat in plain ol' sheet metal is asking a lot.
Not sure how to respond to that slightly veiled challenge to my engineering abilities, other than to say that although the nutserts have been holding perfectly for three years now, if they ever fail I'll make sure you're the first to know.
Not a challenge at all. They are designed for a specific purpose. Light duty fastening. I don't believe holding a seat to the floor would be considered light duty. I've seen plenty used in the wrong application and seen them fail. And the friction from bolt to nutsert corrosion will 99% of the time overcome the compression friction applied when installing these things. No matter if the "light duty" nutsert version or the serrated "heavy duty" version. But I'm not here to tell you how to build your truck. Just sharing my experience.
Light duty? TCI uses nutserts for body mounts on their high-performance aftermarket chassis. They've been holding my Model A body on its TCI frame for over 20 years now.
Nutserts into a 5/16" thick structural member are a completely different animal than ones going into sheetmetal.
If you look at the test strength from Rivnut (in my experience the best nutserts), the sheetmetal tests are done on a panel that is supported on both sides 1/2" from the centerline of the hole. It is not until they get to 0.125" plate that they test the strength against just the mounting surface.
A fully compressed nutsert will have a loading surface that is an annular ring that is a percentage of the diameter of the bolt. It usually ends up being slightly smaller than a standard diameter washer (as opposed to a fender washer). I have not seen your specific setup, so I cannot comment on its structural stability.
As a generic recommendation to someone looking to move a mount, I would say to look at how the stock mount is supported and at least duplicate that. On my truck, the underside of cab where the seat bolts go in is a much thicker section of metal around the bolt. This could be replicated in another location by putting in a backing plate. The purpose of the backing plate is to spread the load out across a larger surface area. The strength of the metal is correctly measured in lb/in2, so increasing the area where the load is applied will reduce the likelihood of structural failure under load.
Last edited by Fibonachu; 08/11/20216:45 PM. Reason: to add more detail on backing plates
Lets not let this conversation get too cheeky. The real test of whether or not a nutsert will hold or fail is a hard collision that I hope never happens to anyone. I use a 3/16 steel strap and 2" washers when I relocate seat mounts on sheetmetal.
Another quality post. Real Trucks Rattle HELP! The Paranoids are after me!
I use a 3/16 steel strap and 2" washers when I relocate seat mounts on sheetmetal.
That won't work for panel truck seats; depending on where you locate the seat, due to baffles inside the pedestal the inside is inaccessible with one's hands to install nuts/washers. I know because I tried it first before I resorted to nutserts.
A wreck would not pull my seat mounts out because my seatbelts are mounted to the floor behind the seat, not the seat itself. And simple math will tell you that the cumulative strength of eight 3/16" nutserts is greater than two 1/2" seat belt bolts.
Originally Posted by Fibonachu
Nutserts into a 5/16" thick structural member are a completely different animal than ones going into sheetmetal.
The original bolts are in sheet metal.
TCI Model A frames are only 1/8" wall, nowhere near 5/16. TCI was originally criticized for using nutserts too, but time has proven them secure.
This is another case of guys warning against something they have never actually done themselves. I've done it, it's worked flawlessly for three years with two-up in the seat and a bunch of horsepower shoving us against the back. Yeah, were both lightweights; maybe those with heavy loads might not want to try it ;-)
This is another case of guys warning against something they have never actually done themselves.
I have torn many rivnuts out of sheetmetal and lived to tell about it, thus why I am far more cautious now. That said, I have given my answer to the OP question. As with anything on the internet, your mileage may vary.
I have torn many rivnuts out of sheetmetal and lived to tell about it, thus why I am far more cautious now.
Not possible to "tear out" - my seat belts are bolted to the floor itself, so there would be no force exerted on the nutserts in the event of a crash.
Originally Posted by MNSmith
If applied to me, this would be an inaccurate statement.
So you actually HAVE installed your seat frame to the pedestal with nutserts? Details please...
Every day I safely drive my panel truck proves the validity of properly installed nutserts and the falsehood of their critics. Thank you gentlemen, and I appreciate the moderators' patience as this debate has managed to remain civil.
