How to secure bolt for folding step ladder?

[gizmo1990]

After stripping back an old step ladder it now needs to be reassembled. During the disassembly the bolts allowing the ladder to fold had to be cut off due to the one shot nature of their design. The inwards facing bolt ends were basically riveted over?

I've got some threaded bolts which fit nicely (see photos) but the question is, what nut should I use to secure the other end? Obviously, just one bolt will work itself loose fairly quickly after opening and closing the ladder a few times. I could use 2 bolts to lessen the chances or use a lock nut perhaps? But they're not really used for this purpose, i.e. securing a bolt which is supposed to allow constant rotation.

Does anyone know if there's a specific bolt or method I should be using in these cases? Preferably something which isn't one shot either. Allowing the ladder to be disassembled if needed.

Any advice greatly appreciated.

 

[JohnD]

If you use coach bolts that are a close fit, they have a square under the head to grip the wood and prevent them turning. They are not fully threaded so choose the length carefully.

put two washers under the nut so they will allow some pivoting without transmitting it to the nut (you can put a tiny bit of grease between the washers if you like) and use a Nyloc (self-locking) nut. You are supposed to use a new nut if you ever take it apart. You can buy half a dozen or so on ebay.

There are other sorts of locking nuts available but you won't want to drill the bolt.

I might also put a couple of greased washers onto the bolt between the wooden pieces, to ease the pivot action.

It's poor design to use an unrestrained bolt as a pivot, since it can undo. I remember a safety bulletin at work when a pulley bolt undid itself and the machine fell. A simple change in manufacturing prevented a recurrence.

 

[gizmo1990]

That's great, thanks a lot for that @JohnD Yep I've got washers already inbetween the wooden pieces. I've found some carriage bolts here that should fit what you suggest.

 

[JohnD]

Yes, that's it, and they're fully threaded.

If the square is very tight (it should be) you can make it pull itself into the hole by tightening a nut, with a big washer, on the other end. Preferably not one of your nylon nuts, which you want to keep pristine. Once the bolt is in, try not to move it.

 

[lostinthelight]

If you tighten nut then cut off the bolt A thread or two long and peen the end over to lock

 

[JohnD]

Need a heavy anvil or something under the head of the bolt while you do that.

 

[lostinthelight]

Need a heavy anvil or something under the head of the bolt while you do that.

Nah! hammer either side would do it, its only to close the thread

 

[foxhole]

You could use a domed nut to lock the end .

 

[Tigercubrider]

How thick is the timber?
you could use a T nut on the inside, and open out the pivoting part, inserting a short metal tube as a bearing.
Then locktite the through bolt to T nut