Elevator Bolts: I don't get it

[Aktundra]

I have removed the shell from a 1963 Bambi, and I have to say, I don't "get it" as far as the advanages of putting elevator bolts back in.
Threaded Rivnuts are a little tricky to install, but pretty easy once you get the hang of it, and in this case they are not "blind" when installing in C channel.
When you figure the cost of flat washer + lock washer + nut compared to a rivnut the cost is about a push either way. A flat head screw with a drop of thread locker, would keep 'em tight, but still allow the bolt to be removed in the future and the floor plywood replaced, without dropping the belly pan.
Below is some practice for another project. Anybody see a draw-back to using Threaded Rivnuts instead of elevator bolts?

Rivet Nut, Stl, 1/4-20, 0.585 L, PK50 - Rivet Nuts - Thread Insert - 3XWX2 : Grainger Industrial Supply

[Jammer]

The head of a flat head screw is not as large as the head of an elevator bolt and does not distribute the stress as widely. Also, in the course of turning the screw while tightening, you may cut more of the fibers in the floor than you would with an elevator bolt.

[perryg114]

They make elevator bolts with slots in them so you can install them from the top. The newer trailers Airstream use these and they thread the frame and cross members and put the screws in from the top. I installed mine from the top and yes you get enough threads to make it work with 1/4-20 screws. You may be able to get the phillips head ones from an AS dealer.

McMaster-Carr

Perry

[Beaker63]

Hey AK,
VTS sells them, but I got some from the local full service hardware store. They didn't have any slots but it would have been easier to install if they did. Smear some bondo over the top and sand flush.
Tim

[Aktundra]

It's not that I cannot get elevator bolts, I can get 'em. They just seem like an undesirable fastener. With no grip at the top ( will check out the recommendation for the slotted version), they cannot be tightened, nor removed. It seems undesirable to HAVE to get at the bottom to remove. The oversized head, would only be marginally better, than just a flat head, but with disadvantages just mentioned.

[barts]

Threading frame and cross members won't work very well on Vintage trailers - there really isn't much metal there. The problem w/ RivNuts is that you'll have a hell of time finding the holes if you ever replace the plywood.

- Bart

[Frank's Trailer Works]

Why do elevator bolts now need slots and when did they become difficult to install? Am I missing a post here?

[perryg114]

You can't put a nut on the inside of a box beam like on newer trailers. The older trailers uses open C-channel so you can get to the back side to put a nut on them.

Perry

[Aktundra]

Just to be clear, I have never installed an elevator bolt in my life. Maybe it's because I have never worked on an elevator, but have seen all kinds of fasteners in all kinds of applications, but I have never seen a elevator bolt.

Just seems to me that if one is unable to grip the top, there is a limit to how tight they can be tightened. I guess one just depends on resistance with the top rubbing against the wood? Just seems it would take longer to install, and still not be able to really get things tight.

Regarding access. It's not that both ends cannot be accessed due to a boxed vs C channel frame. It's just that the entire belly pan needs to be dropped, which means the shell needs to be released, just to get a wrench on a bolt to simply remove a piece of flooring.

Like a said, I just don't get it. I figure the AS guys that designed and built these things in the first place, where professionals, and spent a lot more time than I, in figuring the best way to build 'em. When they weighted the pros and cons of various floor fasteners, I just don't see why the head size (pro) out weights the drawbacks.

no need to flame me, I just don't get elevator bolts !

[perryg114]

You can use any fastener you want and use washers as well. Elevator bolts were used probably to reduce the number needed to get the job done. Some elevator bolts are ribbed and some even have teeth that grab the wood so they can't turn. If you are using something like 3/4 inch thick flooring like on the older trailers you can make a pocket deep enough for a hex head bolt and a washer. I think Aerowood used some smaller bolts and more of them on his rebuild.

Perry

[Lance M]

AK,
Floor attachment can be done many ways. There are advantages and disadvantages to all methods. Airstream used "weld screws" originally. That is what was in my '72. Perry's '81 has something different. See this thread about elevator bolts. I use elevator bolts from Fastenal. I haven't had any problems getting them to tighten from below. Removing the belly pan and using elevator bolts is the best way to replace a floor, in my opinion.

[Wabbiteer]

Elevator bolts are/were for canvas conveyor belts on grain elevators & silos - so its designed use involves an interference fit. Most of the ones available at big box stores these days are knock-offs of a true high temper carbon steel elevator bolt. To get it to clench and start clamping try higher RPM tools; not extreme torque tools just spin the nut fast enough any slippage is minor from the number of turns happening.

[Shacksman]

Now a days Airstream uses these trailer floor screws that are easy to put in from the top. 1" Long Black Torx Wall Liner Screw Redline Accessories and Parts WLS100
Available in different sizes from Fastenal.