Twisted Chains

Joe1 · May 20, 2007

This may sound like a dumb question, but does twisting a chain in order to shorten it reduce it's strenght? I do this on the safety chains on my trailer so they don't drag.

RayH · May 20, 2007

Joe1 said:
This may sound like a dumb question, but does twisting a chain in order to shorten it reduce it's strenght? I do this on the safety chains on my trailer so they don't drag.

Technically speaking, it probably does a little.
Parctically speaking, it probably doesnt matter one bit.

irwin · May 20, 2007

RayH said:
Technically speaking, it probably does a little.
Parctically speaking, it probably doesnt matter one bit.

Ray that is one good answer..ditto, what Ray said..

DieselPower · May 21, 2007

Short answer, yes it does reduce it's load carying capacity. If you need to shroten it you should use a chain shortener. Simply a chain link with a hook on each end.

When I went through Wreckmaster school one of the first thing's they teach you is to make sure your recovery chains never become twisted as it can greatly reduce their working load limit. If the recovery will induce a twist into a chain a swivel should be used. Some rotation of the chain is fine but the links should never fold over each other as you describe.

Joe1 · May 21, 2007

Thanks for the info.

George2615 · May 21, 2007

You could always just use a bungee cord to hold them up.

Joe1 · May 23, 2007

George:

The problem with the bungee cord is that if the hitch fails the chains are still too long to properly hold the hitch and jack post off the ground.

George2615 · May 23, 2007

Joe,
Can't you shorten the chains? or get yourself a couple of these to take up the slack. Each is rated for 2640lb.

john_bud · May 24, 2007

DieselPower said:
Short answer, yes it does reduce it's load carying capacity. If you need to shroten it you should use a chain shortener. Simply a chain link with a hook on each end.

When I went through Wreckmaster school one of the first thing's they teach you is to make sure your recovery chains never become twisted as it can greatly reduce their working load limit. If the recovery will induce a twist into a chain a swivel should be used. Some rotation of the chain is fine but the links should never fold over each other as you describe.

Hmmm, I would not have thought it would make a difference. Learn something new everyday. Does it reduce the load capacity due to the pull being across the width vs end to end?

jb

Joe1 · May 24, 2007

George:

Thanks.

I'm going to see if I can shorten the chains without a lot of work or use the links. I'm getting lazy with old age.

john_bud:

If I remember right, some prisoners were able to break the chains on handcuffs (with great difficulty) by twisting them somehow when they couldn't break them by just pulling on them, so it must weaken the chain substantially. I think that was the reason for the rigidly hinged cuffs.

DieselPower · May 24, 2007

john_bud said:
Hmmm, I would not have thought it would make a difference. Learn something new everyday. Does it reduce the load capacity due to the pull being across the width vs end to end?

jb

It was explained to me this way. When you pull on a normal welded chain link when the chain is not twisted the load tries to pull the weld apart which is very difficult. When the links get twisted it places side loaded forces against the weld and can break them.

john_bud · May 24, 2007

DieselPower said:
It was explained to me this way. When you pull on a normal welded chain link when the chain is not twisted the load tries to pull the weld apart which is very difficult. When the links get twisted it places side loaded forces against the weld and can break them.

Hmmm.... Brain pan gears starting to gind.... I thought steels are rated by tensile strength. That is the force needed to pull them apart in a stretching manner. An expample would be pulling a bolt head directly away from thread end. My understanding is that is done as it is the lowest force to cause failure. It's harder to compress a bolt to failure or shear one to failure - right?

So assuming that you were taught correctly that twisted chain is lower strength than straight chain, then there must be some sort of bending forces induced when the twisted chain is pulled.

Too bad there isn't a mechanical engineer reading this...

jb

Olmike · May 24, 2007

I twist my chains around each other under the tongue.Makes them shorter & if something does happen the tongue will be supported by the crossed chains & not the road.
Mike

Joe1 · May 24, 2007

Olmike:

I do the same thing and did have the coupler come off the ball once. I was helping a friend move some trash to the dump with my trailer and my vehicle. It was too tight to back in to the loading area so we moved it by hand on the dolly wheel. We loaded the trailer and my friend reattached the trailer to the Jeep. Stupid, Stupid, Stupid me, I didn't check to see that he had snapped the coupler closed and attached the safety link.

We hit a bump and the coupler came of the ball with a heck of racket. The chains kept it attached to the car and other than a bent jack post in the front and a little ding in the bumper, so harm. 5 Seconds later the California Highway Patrol pulled up behind me. Not noted for their great sense of humor, the nice Officer helped us reattach the ball and this time I checked to make sure it was locked. I did NOT get a citation. but probably should have. Thank you again Officer.

Now I keep the chains even shorter. I see many trailers with the chains so slack they might keep the trailer and the tow together, but there will be no control of the trailer and a lot of damage to the tow and the trailer.

radman1 · May 24, 2007

George2615 said:
Joe,
Can't you shorten the chains? or get yourself a couple of these to take up the slack. Each is rated for 2640lb.

George
Those kind of splice links are probably a bad idea. The strength limit/capacity of those, is much less than a chain link of the same size.

Joe1 · May 24, 2007

Radman:

I'm not sure on the safety issues of the splice links. I know they are the way most RV's connect their "Dingy" safety cables between the RV and the dingy.

Someone suggested they are rated at 2,600 lbs each which probably has a 25 - 50% safety margin. A twisted chain may still be stronger than the links.

john_bud · May 24, 2007

Joe1 said:
Radman:

I'm not sure on the safety issues of the splice links. I know they are the way most RV's connect their "Dingy" safety cables between the RV and the dingy.

Someone suggested they are rated at 2,600 lbs each which probably has a 25 - 50% safety margin. A twisted chain may still be stronger than the links.

I have NEVER seen a spec that high for those. 300-600# is the norm. Maybe that one is super strong? If so, where was is purchased from? I'd like to get some....

jb

Joe1 · May 25, 2007

john_bud:

George2615 earlier here in this thread sugested the 2,640 lb rating.

radman1 · May 25, 2007

Joe1 said:
john_bud:

George2615 earlier here in this thread sugested the 2,640 lb rating.

Like John bud said, I have never seen them rated that high. I have had these pull apart with not very heavy loads on them. Like you, I have seen them used to connect safety chains to vehicle. A hook is much better. Maybe a large threaded splice link on a small chain would be OK?

George2615 · May 25, 2007

I haven't used mine for the purpose of shortening a length of chain. In fact I haven't used them at all yet which is why the tag was still on them. I bought them to connect a hook or grab link to a chain end.

The tag on them shows the rating of 2640lb per unit. The rating is also stamped on them as SWL 2640 (Single Weight Load). I believe I purchased them from TSC. They are 3/8", made by National mfg in Sterling Ill. TSC has three types of safety chain on their site rated for 2000#, 3500-7000# using 2 chains, and 10-14K using 2 chains.