After going through this myself recently, sometimes when wrenching on junk you may find yourself using a "crow's foot", or "offset" extension piece. This will definitely be the case if you are doing tubing nuts, etc. It made me recall about how some people get confused as to when you need to do it. I recall a long time ago one guy saying it didn't make any difference regardless. Math proves him wrong every time.
Now, the easiest way to do it is if you have the room, get the crow's foot 90 degree angle of the torque wrench. This way, you don't change the effective torque handle length of the bolt/nut center to torque lever force point (center of grab handle). No math. Which is a win.
But, sometimes you don't get that choice. You may be off at some sort of angle, whether extending the effective length or reducing it, depending on where the crow's foot lands.
The basic formula for using the math is pretty straight up. You caculate the "new" effective length with the crow's foot as a percentage x the torque spec for the bolt/nut = torque setting read on the torque wrench.
Rather than bore you explaining everything, I'll credit Tekton for the following crow's foot calculations in pictures.
L = effective handle length
T1= Torque spec for fastener
C= Distance between center of drive to center of fastener as a straight line. No need to do angle calculations. Think of it as how much the effective length is changed, either positive or negative.
T2= Torque reading to reach on torque wrench. Set click-types to this, read T2 on beam type.
Here's two examples showing how you apply the math for a fastener to be torqued to 80 lbs/ft.
Note that in example #2, if you shorten the effective torque length, (L), you will require a tad more torque set or read at T2. This is because you need to subtract C from L. The way it's shown in the picture can be a tad misleading if you're not looking out for it. Note the math formula at the bottom of the #2 diagram does show you subtracting the 1.1" change in length.
If you want to use a desktop computer to calculate it, Tekton has one:
www.tekton.com
If you carry your phone around in the garage, Norbar has apps for iPhone or Android so you don't have to remember math.
That's it. Hope this helps.
Now, the easiest way to do it is if you have the room, get the crow's foot 90 degree angle of the torque wrench. This way, you don't change the effective torque handle length of the bolt/nut center to torque lever force point (center of grab handle). No math. Which is a win.
But, sometimes you don't get that choice. You may be off at some sort of angle, whether extending the effective length or reducing it, depending on where the crow's foot lands.
The basic formula for using the math is pretty straight up. You caculate the "new" effective length with the crow's foot as a percentage x the torque spec for the bolt/nut = torque setting read on the torque wrench.
Rather than bore you explaining everything, I'll credit Tekton for the following crow's foot calculations in pictures.
L = effective handle length
T1= Torque spec for fastener
C= Distance between center of drive to center of fastener as a straight line. No need to do angle calculations. Think of it as how much the effective length is changed, either positive or negative.
T2= Torque reading to reach on torque wrench. Set click-types to this, read T2 on beam type.
Here's two examples showing how you apply the math for a fastener to be torqued to 80 lbs/ft.
Note that in example #2, if you shorten the effective torque length, (L), you will require a tad more torque set or read at T2. This is because you need to subtract C from L. The way it's shown in the picture can be a tad misleading if you're not looking out for it. Note the math formula at the bottom of the #2 diagram does show you subtracting the 1.1" change in length.
If you want to use a desktop computer to calculate it, Tekton has one:
How to Use a Torque Wrench with a Crowfoot Wrench | TEKTON
Learn how to accurately use a torque wrench with a crowfoot wrench to measure torque. Use the included Torque Conversion Calculator.
www.tekton.com
If you carry your phone around in the garage, Norbar has apps for iPhone or Android so you don't have to remember math.
That's it. Hope this helps.
