Torque Loss

[Moose-LandTran]

Reading the other thread about the torque sticks got me wondering, can you "lose" torque through a long extension?

i suppose with an impact gun, the string steel in the torque stick will flex and absorb some of the forces and energy being put through it. but with a constant application of force what do you lose?

i was told by my old manager to always use the shortest possible socket for removing wheel nuts. i didn't listen, partly because i can't see how you could "lose" torque, but mostly because my gun put out 1,100lb/ft. and that's enough to break any car wheel nut loose.

i can't see where you can lose the torque, there's not loss though friction if the extension isn't touching anything, and it doesn't really make any sense either.

can anyone shed any light on this?

Many Thanks,
Moose.

 

[Blacknwhitepit]

Reading the other thread about the torque sticks got me wondering, can you "lose" torque through a long extension?

i suppose with an impact gun, the string steel in the torque stick will flex and absorb some of the forces and energy being put through it. but with a constant application of force what do you lose?

i was told by my old manager to always use the shortest possible socket for removing wheel nuts. i didn't listen, partly because i can't see how you could "lose" torque, but mostly because my gun put out 1,100lb/ft. and that's enough to break any car wheel nut loose.

i can't see where you can lose the torque, there's not loss though friction if the extension isn't touching anything, and it doesn't really make any sense either.

can anyone shed any light on this?

Many Thanks,
Moose.

I think this torque loss issue was discussed a while ago

Here perhaps: http://www.garagejournal.com/forum/showthread.php?t=4751&highlight=torque+diagram


-BWP

 

[grzmonkey]

Moose,

Loss of torque can happen with any tool ... including impact wrenches...the longer the anvil the greater torque loss. So a 1/2" impact with a 2 inch anvil (most prominent in tire shops will not apply as much torque as a short anvil tool. Couple this with the flip socket on teh 2" anvil and you see evfen greater torque loss...on 1" guns with 6" anlis you see the same principle apply .... this is where torque sticks come into play. They "bend" to absorb torque. By the way, your 1100 ft lb gun is marketing hype ... IR came up with this formula as a marketing ploy. It takes only two thirds of applied torque to break afasterner loose so when they say 1100 ft lbs of nut busting torque that means they have run a bolt down to 1100 ft lbs (on a Skidmore torque testing machine) and it take approximately 700 fts lbs to loosen the nut ... check your gun. I bet it is rated at 700 ft lbs of max torque. Most companies play the torque game as a selling tool...like HP in a car. Consider weight, size and power ... in that order. Who needs 1100 ft lbs on a standard vehicle anyway??? Do yourself a favor and get a trial on the CP 7740...2.7 lbs, small comact design and 500 ft lbs or real, honest torque

 

[Merkava_4]

There's a pretty long thread about this very subject.

Happy reading.

http://www.garagejournal.com/forum/showthread.php?t=4751&showall=1

 

[TNToy]

You lose torque with an impact-type tool due to the torsional twisting of the extension... Similar to the torsion bars used as springs on GM pickups. It 'dulls' the power of the gun's hammering.

Using a breaker bar or handtool, it's not really an issue so much.

 

[kartracer55]

Think of it like this... you have a long extension and as the gun hammers, it twists a certain amount over the length of it. So while the nut at the end of the socket on this extension provides resistance, some of the torque goes into twisting the extension too.

I use flip sockets at work for wheel work simply because it is convenient. Every now and then I will have a tough lug nut (many times on european cars with lug bolts) where I need to grab a shorter socket. A short vs. deep socket does not matter as much as removing the 3 inch extension and extra connection that comes with the flip socket.

If you want a little experiment, Tighten down a lug nut until it stops moving with a flip socket, then grab the short socket. You will get a little more out of it...

 

[Moose-LandTran]

i figured there'd be some loss with an impact. but with hand tools i couldn't see reason for loss, just wanted to confirm.

and grzmoney, even 750lb/ft should be enough to move any bolts i come accross day-to-day.

 

[grzmonkey]

Moose, agreed on 750 ...so why do the hype the torque rating to 1100 ...sets up false expectations and can't apply that much torque on run down...just calling out the issue of torque that most manufacturers "round up"

 

[kartracer55]

Moose, agreed on 750 ...so why do the hype the torque rating to 1100 ...sets up false expectations and can't apply that much torque on run down...just calling out the issue of torque that most manufacturers "round up"

That is a break away torque rating. The 2135ti max can hammer at a bolt tightened to 1100ftlbs for something like 6 seconds and it will loosen it. Its all about the fine print