Torque Wrench

What th' heck is a torque wrench ?!!!!!

|UPDATED|11/17/2004 8:46:34 PM (AZT)|/UPDATED|

To answer your original question,if you are torquing your head bolts with a 1/2" drive 4 or 6 inch extension there will be no change. A crows foot changes the rotational center but this is a different issue! It is true that using a 3 foot long 3/8" extension would twist is correct but you would never do that! Let's get real here and give people usable information.
Steve

with a 6" extension i would add 5% as per my post above

If your extension deflects 5 % you will still have the same force at the socket you will just have to turn it a little further to compensate for the deflection.And a 6"
!/2" drive extension won't deflect 5%@65 lbs/ft.
Steve

Steve said: If your extension deflects 5 % you will still have the same force at the socket you will just have to turn it a little further to compensate for the deflection.And a 6" !/2" drive extension won't deflect 5%@65 lbs/ft. Steve

changing it from 65 to 68 lbs is pretty easy too.

Go to http://ww3.hti.org and search on the list of manufactures. Click on CDI's web site and look at their "Torque Facts - use of Adapters". You'll get the info your looking for.

The HTI web site is the best place to get most all of the major Hand Tool mfg's web sites, telephone #'s, addresses, helpful technical info, etc.etc.

My understanding was that adding additional leverage at the end of the torque wrench would not change the value but changing the distance between the socket and wrench would change the applied torque. Enough to matter for a 4" extension? not sure? I guess the concensus is to give it a little more.

The reason I ask is in a practical sense if I am torqing to 50 ft/lbs using my old style wrench (indicator on a scale) my accuracy of being able to hit the number exact is probably no greater than the 5% extension inaccuracy we are talking about, especially if I don't have a clear line of sight to the dial which is frequently the case.

bob_robert said: Go to http://ww3.hti.org and search on the list of manufactures. Click on CDI's web site and look at their "Torque Facts - use of Adapters". You'll get the info your looking for. The HTI web site is the best place to get most all of the major Hand Tool mfg's web sites, telephone #'s, addresses, helpful technical info, etc.etc.

the link is found here http://www.cditorque.com/main.html

just click on torque facts in the NAV bar.. it address crow foot adapters..

now im on a mission to find "official" rules for extensions just as a matter of curiousity

cthulhu said: now im on a mission to find "official" rules for extensions just as a matter of curiousity

I looked and looked and couldnt find any definitve answer. I found quite a few sources that said "never use a socket extension" when torquing <some item>"

but no one saying how much to compensate. I even found some tool vendor claiming that the elasticity of their extensions was less than that of other brands.

If you knew the specific elasticity of the metal (steel is VERY elastic) then you could calculate it, and while I may be a geek.. Im not enough of one to try to find elasticty ratings for various tool manufacturers.

|UPDATED|11/19/2004 1:44:24 AM (AZT)|/UPDATED|

There are way too many variables to correctly calculate the torque loss. Refer to Ben's rule of thumb.
Even a 1" extention will lose some torque. Not enough to make a pratical difference, but some. The longer it get the more you lose. There are no exceptions to this. There are varying amounts, also dependent on the diamiter and tensile, and elastic strength of the extention.

Ben, That's why you haven't found a printed chart. Too many possibilities. You may find such a chart through a specfic tool company.

(yes, I'm still at the conference, but got a few minutes to get on line. Not enought time to get all caught up)