A better frame flex solution

[huntindog]

So far the "fix" has consisted of 1/2" lag bolts to properly fit the 1/2" holes in the frame, and some adhesive to hopefully keep the bolts from backing out.
I would much prefer a mechanical method of preventing bolt backout.
I previously thought about tack welding the bolt heads to the frame. I discarded that idea because welding inside a coach has a high fire risk.
A better idea finally hit me.

Some small steel plates about 1" square, and 1/8" thick with a hole drilled in the center. Some self tapping hex head metal screws to fit the hole.
Place the square up against a lag bolt hex head flat. Secure it with a self tapping screw into the frame. That bolt will never back out on it's own again...But if it needed to be removed later for some reason, it could be.

On edit: I am not sure if the self tapping screws will penetrate the frame. If not, then a small pilot hole will need to be drilled.

Note to moderator:
I posted this in a different thread, and decided that this needed it's own.
I will try to delete the other one.

 

[jjbbrewer]

I would much prefer a mechanical method of preventing bolt backout.

Interesting thought. I had the dealer do the TSB on my upper deck flex and it seems to be working fine, but I didn't think about bolt backout.

In aeronautical mechanics (and motor racing), there's a pretty wide spread usage of safety wire to prevent fasteners from loosening. I could see doing this to the bolts along the frame to prevent back out and to allow removal at some time. You'd just have to pull the bolts out (one by one!) and drill the heads.

 

[Hoopy Frood]

Curious if there's evidence of the proper sized bolts backing out once they're tightened correctly.

 

[huntindog]

Interesting thought. I had the dealer do the TSB on my upper deck flex and it seems to be working fine, but I didn't think about bolt backout.

In aeronautical mechanics (and motor racing), there's a pretty wide spread usage of safety wire to prevent fasteners from loosening. I could see doing this to the bolts along the frame to prevent back out and to allow removal at some time. You'd just have to pull the bolts out (one by one!) and drill the heads.

View attachment 191218

I thought of that. It takes a special tool. and the knowledge of how to do it correctly.

 

[jjbbrewer]

I thought of that. It takes a special tool. and the knowledge of how to do it correctly.

9 in. Safety Wire Twisting Pliers

Amazing deals on this 9 In. Safety Wire Pliers at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Since you don't have to be mil-spec quality, it's actually pretty easy to do.
Truly, the hardest part is drilling the bolt heads without breaking too many drill bits.
It's kind of a better version of using bailing wire to fix something.

 

[coglesby]

Lock washers?

 

[huntindog]

9 in. Safety Wire Twisting Pliers

Amazing deals on this 9 In. Safety Wire Pliers at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Since you don't have to be mil-spec quality, it's actually pretty easy to do.
Truly, the hardest part is drilling the bolt heads without breaking too many drill bits.
It's kind of a better version of using bailing wire to fix something.

The other downside is that the bolts need to be removed to drill the heads. Every time a lag bolt is removed from wood and reinstalled, it gets weaker.

 

[huntindog]

Lock washers?

Better than nothing but just barely.
the lags go into wood. If it were bolts into metal that could work well.

 

[Steven@147]

I safety wired many a bolt when in the Navy. Idea is if one bolt starts to loosen, it pulls the adjacent bolt tighter. Still have those safety wire pliers.
Problem is the lag bolts are too far apart for that. I guess that's why I've read they are using some kind of glue on the threads when they put the new 1/2 bolts in? It would be nice to use a flat washer and lock ring. At a 3 inch length makes you wonder how close the bolt is to going through the side of the RV? Don't think you can get a 3.5 length bolt to account for the washer and lock but then go through metal box filled with wood strip but not go through the outside wall?

 

[huntindog]

I safety wired many a bolt when in the Navy. Idea is if one bolt starts to loosen, it pulls the adjacent bolt tighter. Still have those safety wire pliers.
Problem is the lag bolts are too far apart for that. I guess that's why I've read they are using some kind of glue on the threads when they put the new 1/2 bolts in? It would be nice to use a flat washer and lock ring. At a 3 inch length makes you wonder how close the bolt is to going through the side of the RV? Don't think you can get a 3.5 length bolt to account for the washer and lock but then go through metal box filled with wood strip but not go through the outside wall?

From the pics I have seen, there is not a lot of wood there

 

[goducks14]

A two part epoxy would fill the gaps and create a much stronger bolt to wood attachment.

Loctite Instant Mix 1-Minute 0.47 oz. Epoxy Translucent Yellow Syringe (Each) 1366072 - The Home Depot

Loctite - Instant Mix 0.47 fl. oz. Epoxy - Get exactly mixed adhesive with precision placement with the help of this epoxy, featuring an advanced self-mixing nozzle applicator. Can be sanded or painted

www.homedepot.com

There's other two part epoxies on the market of the same type that could work better.

 

[Jhdarizona]

So far the "fix" has consisted of 1/2" lag bolts to properly fit the 1/2" holes in the frame, and some adhesive to hopefully keep the bolts from backing out.
I would much prefer a mechanical method of preventing bolt backout.
I previously thought about tack welding the bolt heads to the frame. I discarded that idea because welding inside a coach has a high fire risk.
A better idea finally hit me.

Some small steel plates about 1" square, and 1/8" thick with a hole drilled in the center. Some self tapping hex head metal screws to fit the hole.
Place the square up against a lag bolt hex head flat. Secure it with a self tapping screw into the frame. That bolt will never back out on it's own again...But if it needed to be removed later for some reason, it could be.

On edit: I am not sure if the self tapping screws will penetrate the frame. If not, then a small pilot hole will need to be drilled.

Note to moderator:
I posted this in a different thread, and decided that this needed it's own.
I will try to delete the other one.

any chance you could post pictures of how you see this working?