Question about torque wrench

[shortleg]

   If I have to add a 1/2 inch to 3/8 adapter to my wrench
because I do not have a 1/2 inch drive socket that size.
  What affect dose it have on the torque reading ?
           shortleg

[Paladin528]

wrench setting = desired torque x wrench length / (wrench length + extension length)

so if you were 80 pound feet specified with a 3 inch extension (24 inch wrench) then it would be
Ts=80*24 / 24+3
Ts=1920 / 27
Ts=71.1lb/Ft

I should add that this only applies when the extension is in line with the wrench.  the formula changes when the extension is at an angle.

Here is a good guide for how to calculate.
http://www.trialsnuts.com/torqued.pdf

[Roidfingers]

Why would an extension from the wrench to the socket have any effect at all on torque ?
 I could understand if you were adding an extension out beyond the torque sprocket forward in a lineal way.

[Paladin528]

I red the post wrong.  I was thinking of an extension to the LENGTH of the wrench.  Just stepping it down has ZERO effect on the applied torque.

[Patrick]

   If I have to add a 1/2 inch to 3/8 adapter to my wrench
because I do not have a 1/2 inch drive socket that size.
  What affect dose it have on the torque reading ?
           shortleg

None.

[shortleg]

  Thank you guys
     shortleg[Dave]

[The emperor has no clothes]

I red the post wrong.  I was thinking of an extension to the LENGTH of the wrench.  Just stepping it down has ZERO effect on the applied torque.

Whew ! I thought I was going to have to do some algebra . 

[westnek]

al who????  maybe I missing  something I just go realy  tight,, tight, and a bit tight,  , snug ==that's very interesting post  merry Christmas to all  west

[gregk]

Yup, as said it does not change nor would an extension  90deg. to the handle change the value.  Only if you are extending the length of the beem like using a crowfoot wrench for example. Try not to use a universal joint.   I think you might be able to bring up a formula at snapon tools or ask your smart phone for a formula to calculate torque when extending the length of the handle.

[Ricky-D]

It would seem to me that if you have to reduce the drive size to accommodate a socket, that you are using the wrong tool

and are increasing the chance of twisting off the fastener or stripping out the threads. large torque wrenches on small

size bolts/nuts is the prescription for failure. Torque wrenches are probably responsible for the majority of fastener

problems such as ripped out threads and twisted off bolts and nuts.

***

[WintrSol]

It would seem to me that if you have to reduce the drive size to accommodate a socket, that you are using the wrong tool
***

I agree - a 1/2" torque wrench is often rated up to about 150lb-ft (sometimes more), and rated accuracy is given in a % of full scale. A really expensive one may be rated +/-1% or less, but that's still +/-1.5lb-ft, so when set to 20, you could actually be at 18.5 or 21.5, which could be enough for stretching a fastener or pulling threads out of aluminum. You should always use a torque wrench closer to it's limit, not near the bottom of the range, IMO.

[Patrick]

Now maybe, just maybe, Shortleg just happens to have only a 1/2" t-wrench and needs to use, lets say, a 3/4" socket.  But, lets say his 3/4" 1/2" drive socket is missing/broken and his only option is to use his 1/2 to 3/8 adapter and his 3/8" drive 3/4" socket.

It appears to me that that would be a similar scenario to his original post and a possibility for his question.

He may have some idea as to what tonnage he wants to set the fastener to/at, and, knows to sneak up on that setting.

Just saying.