Do rivet nuts work?
 

I have a steel floor in my 1930 Model A Ford. At present the seats are held to the floor by bolts that go through the floor with a nut underneath the floor. Yes when I want to remove the seats, I need a second person with a wrench underneath the car to stabilize the nut while I remove the bolt from inside the car. Someone suggested an item called a “rivet nur“. This would supposedly eliminate the nut underneath the floor which can come loose. Does anyone have any knowledge of this item and how well it works? I have seen this item and it looks like it should work fairly well but since I have never used them, I am seeking opinion from the membership. The size that I would need to use is for a 1/4 inch bolt. Has anyone used this item? Comments would be appreciated.

Re: Do rivet nuts work?
 

Similiar to a clinch nut?

Re: Do rivet nuts work?
 

Yes, I have used them when installing PS on my 53' Merc, to fasten the end frame bracket to the car. They were used by the factory originally, for the same purpose. These are way heaver than you will be using, but the application is the same.

I have always been able to reach around to get both ends of the bolt and nut, when removing or installing the seat, but your reach might be more. It depends on how good the metal is on your floor and floor brace. If it is at all marginal, you could just rip out the nut when adjusting the seat. I use additional heavy large washers on the bottom,below the floor.

Re: Do rivet nuts work?
 

Occasionally a rivnut will spin when trying to remove a bolt. You then have a fun situation, trying to remove it. If you have access to the bottom side, then it’s not bad. If it’s in a cavity, then “Houston, we have a problem”!

Re: Do rivet nuts work?
 

I’ve used them in a few applications and they work great. I just don’t know if they’re prone to loosening and spinning over time which could make it a hassle to remove the bolt.

Re: Do rivet nuts work?
 

Leonard & Tom
They may have an application. But, always a but, they are very prone to spin.
I don’t use them….for anything.
Just imho …from experience

Re: Do rivet nuts work?
 

Well, ...what you are asking is a loaded question IMO. They are handy however like others stated above, I have found they don't work as well with light-gauge sheetmetal uses for that reason. Where they shine IMO is in boxed tubing applications where you want to attach something like an electric fuel pump to a piece of tubing and don't want to fasten it with a thru bolt.

With that said, are you certain using ¼" bolts is/are strong enough for that application? -especially if light sheetmetal is used?? In your situation, maybe use some 0.250" wall flat bar (-maybe stainless that can be polished??) that can be threaded in each location of your seat bolts. Then use one or two long bolts to draw the flatbar up to the floor pan, and start threading in your regular length seat bolts. Once those correct length bolts are tight, remove the longer bolts and install the remaining correct length bolts. By doing this, the flat bar spreads the load over a greater area, ...especially in the event of an impact where the seats have a better chance of not ripping out of the floor pans.

Re: Do rivet nuts work?
 

I think that’s what I said…..it’s trouble if they spin.

Re: Do rivet nuts work?
 

To Brent, I had thought about using .25 x 1.5 steel bar underneath the cabin floor and tapping it to receive the seat bolts. I realize that using the flat bars would be very sturdy and also strengthen the floor. When I considered the cost of materials at nearly $100. In addition, I don’t always have an extra pair of hands available to help me. That’s why I considered going the rivet nut route. The rivet nut method I can do all by myself without assistance and for a significantly lower cost and much less project time spent. I still haven’t made up my mind because I do appreciate safety. Making decisions like this is never easy.

Re: Do rivet nuts work?
 

I used them in refrigeration hardware applications, and as mentioned, they don’t always grab well and spin.

Re: Do rivet nuts work?
 

The floor of a 1930 Model A is wood. You need these T nuts https://www.google.com/search?q=imag...hrome&ie=UTF-8
They are CHEAP and work very well but lubricate the screw/bolt you use.

Re: Do rivet nuts work?
 

To clear up a minor misunderstanding, the floor in my 1930 Model A is not wood. The floor is a modern steel floor. It is for that reason that I could use rivet nuts if desired.

Re: Do rivet nuts work?
 

I used rivet nuts to install my handmade metal floor pan beneath my roadster. works perfectly and I've had it in and out multiple times with no issue. I've been dealing with rivnuts for a long time as I was a bicycle tech for a long time, they are used to hold water bottle cages to the frames. The main issues I've had were the fastener seizing into the rivnut . Corrosion from perspiration will lock the two pieces together then when loosening cause them both to spin. Antiseize, grease or wax goes a long way here.

That said I'd say there isn't too much to worry about using rivnuts. if there's an issue file the head down or drill and they pop right out. In a bike frame they are captive so there its a problem there with removing from the tubing. If there's clearance behind it for it to come out it's not an issue and I wouldn't overthink it.

EDIT I guess I missed that you intend to use these to hold the seat to the floor, not the floor to the frame. I would say rivnuts are probably not strong enough for this application.

Re: Do rivet nuts work?
 

I used them on the frame of the car, how thick is the metal floor?

Mine were hexagon, going into hexagon holes, you will be probably be using round. Could you tack weld them after installation?

Re: Do rivet nuts work?
 

I would only use them where there isn’t a better option and only in a spot where you can cut/grind them out if they fail, since drilling them out might not be an option.

Re: Do rivet nuts work?
 

How often do you remove the seat?
you could braze nuts to a strip of metal and a couple of screws would hold it.

The nutserts installed in a hex shaped hole don’t spin as easy, I have used them for years on Mercedes for license plate mounting

Re: Do rivet nuts work?
 

If welding is an option, maybe assemble with a nut and wide fender washer. Tack the washer to the sheet metal in a few spots and tack the nut to the washer.

Re: Do rivet nuts work?
 

While this would be a "cheap" option, how much is your life worth? Or the life of someone riding with you? What happens to those seats in an accident with only these riv-nuts holding them to the floor pan? Those comments about them spinning attest to how little it takes to disrupt their "capture" in the metal they're mounted in. Next question ................. How sturdily would you like seats mounted in your everyday vehicle that would most likely have all kinds of other protection to avoid bodily harm in an accident?

Not trying to pick on you here ............. just thinking of keeping you & yours safe. They call them accidents when you have no idea when they're going to occur.

Re: Do rivet nuts work?
 

I appreciate all your responses. I have read everyone of them and thought carefully about everything you guys have said. I have finally decided how to handle this situation. I will remove the two seats, install two lengths of steel bar, length wise under the floor of the car. The two bars will be 36 x 2 x 3/8. I will attach them to the underside of the cabin floor with steel pop rivets. Then I will locate, Mark, drill and tap these bars for 3/8 inch diameter bolts And tap threads into the bars. Then I will use 3/8 inch bolts to secure the two seats to the floor of the car. I feel as though this type of installation will be quite strong and strengthen the steel floor as well as provide a very secure
Mounting for the seatbelts. How does that sound to all of you? Comments, anyone?

Re: Do rivet nuts work?
 

Seat Bolt should be very secure especially in a hot rod. I would go with flat bar stock like you're talking about, attach that to both ends of the body rail frame, drill and tap for truss head machine screws instead of rivets. Drill the holes for your seats (and seat belts) then use cage nuts, you can weld them on or drill and bolt them. All this is a little extra money and work but way better in the long run for ease and safety.


https://www.farm-fresh.co.uk/wp-cont...-8-24-Cage.jpg

Re: Do rivet nuts work?
 

I have used them for over 40 years and they do have certain drawbacks , I try and use the riv nuts with the knurled out side perimeter, the knurled type have a considerably better grip, My preference is to use the weld on nuts whenever possible .

Re: Do rivet nuts work?
 

The seat belt topic has been discussed on this site before and would be worth looking up, before starting. Mounting belts to the body and how the body is secured to the frame among other issues come into play.
Seat belts may give a false sense of security if the integrity of related parts aren't considered in the process.
I don't mean to be negative, just want you to have a more detailed picture before you start.

Re: Do rivet nuts work?
 

Sounds like a plan. If it were me I would probably also add a washer and nut to the bottom of the bolt, after it has been threaded through the plate, but that is just me.

Re: Do rivet nuts work?
 

Again, thanks for great suggestions. Maybe it would be better to use screws to attach the steel bar to the car body rather than rivets. It’s more work, but perhaps better in the long run. Instead of the cage nuts, I will drill and tap the steel bars to act as nuts for the bolts attaching the seats to the car. I do need to be careful, though, and work within the confines of the tools and equipment that I have available. I have no access to a welder, overhead lift, vice, etc.. All I have are basic hand tools, a tap and die set, a power drill, and a rivet tool. Literally, therefore, I am by definition a shade tree mechanic.

Re: Do rivet nuts work?
 

When i use Riv-Nuts, I install them with a little bit of epoxy to help prevent spinning.

Re: Do rivet nuts work?
 

If you're going to solve the problem by threading the bolts into the bars, you are going to need some way to prevent the joint from loosening under vibration. I suggest a locknut. A nyloc nut might work, or you could go for the period look by using a castle nut and cotter pin. You would need to use drilled bolts but I bet there's a drilled bolt in the standard Model A fastener set that would suit this application.

Re: Do rivet nuts work?
 

5/18x18 would be fine - it's what Detroit uses. Making the mounting strong enough that it doesn't tear through the floor in a crash is the goal. A 2-3" 1/8" flat plate tacked to the floor should be enough. That will also be thick enough to hold the RivNut. My seat mount is 1x2 .090 tubing with RivNuts.

Re: Do rivet nuts work?
 

I was always taught that the thickness of the nut should match the diameter of the bolt. I am using 3/8 inch bolts to mount the seats so I will use 3/8 thick steel strips and tap them 3/8 to match.

Re: Do rivet nuts work?
 

1.5 x dia will get you the max holding power a bolt/nut can offer. % of Thread engagement (class of fit) is also a factor. Fine thread has more holding power than coarse.

Re: Do rivet nuts work?
 

I've used multiple different type of rivet nuts & nutserts over the years. They are common in aviation. Rivnuts can be sourced with an anti-rotational key formed into the flange. A key slot has to be filed into the hole drilled to accept the keyed rivnut. They are available in open and closed end and in multiple materials from aluminum to stainless steel. Lots of different lengths and thread sizes are available.

If the screw thread protrudes into a swampy area then the fastener can corrode and make it very difficult to remove. A lot of them come loose and rotate in the hole due to this. The closed end type will prevent corrosion of this type if anti-seize is utilized.

A person might consider a model A type D-nut but they aren't much easier to install and near impossible on blind installations.

Re: Do rivet nuts work?
 

Rivet nuts are threaded inserts into a hole that are crimped into place with a special tool that threads into the rivet then is squeezed to tighten the rivet part of the rivet nut to hold it into the hole. If the hole is not drilled properly or is oversized, you will have problems. If the rivet is not crimped properly you will have problems. If you are in a high torque requirement setting, you will have problems. But if you are doing light duty applications they are great. On 1960’s Mustangs, Ford used a large scale rivet nut for steering arm and clutch pivot frame mount applications. I won’t say they are perfect, but they were pretty effective. I liked the comment I saw above about some JB weld used in combo if you are concerned. If I ever had one that didn’t set to my satisfaction—real simple drill it out and do it over or go to real nut/washer application. I like rivnuts, just choose the application appropriately.

Re: Do rivet nuts work?
 

After all this discussion about Rivet, and how sometimes they rotate in their mouth, I finally thought of a solution. I may not be the first one to think of this, but I haven’t seen anything in print about this method. I decided to a “keyway“ in the lip of the rivet I wanted to immobilize. Here’s how I did it:
I took a sharp punch and carefully made a dimple in the flange of the rivet. I wanted to immobilize. I then cut length of paperclip to use as my “key“. I took an appropriate sized drillbit that would provide a snug fit for the paperclip. Taking a centerpunch, I put a dimple in the flange of the rivet so that my drill bit would not wander. I then carefully drilled through the flange of the rivet and the metal underneath I then coded the rivet with some clear five minute epoxy And worked the paperclip in and out of the drill hole a few times before leaving it in place while the epoxy set up. I let it sit overnight and the next morning I use a flush nipper to cut the paper clip off flush with the lip of the rivet. On a couple of rivet knots that were larger such as 3/8 inch I did two paperclip keys to ensure that I can tighten the screw to appropriate tightness. It’s only been a few days since I did this but so far everything seems to be working just fine.