Alamo JD-5225 - Manual (Page 13)

© 2005 Alamo Group Inc. Section 1 - 5
Switch Blade (JD-5105-5205-5225-5325-5425-5525, Asy. Man) 05/05
Figure 1
USING AN ADAPTER WITH A TORQUE WRENCH
If an adapter is attached to the drive of a torque wrench, the wrench will not give actual torque
indicated by the setting of the handle. A simple formula however, allows you to figure out what the
setting should be to deliver a predetermined amount of torque at the end of any adapter to the
fastener.
The following letters are defined as:
A = Length of the torque wrench when set at the middle scale setting (inches).
B = Length of adapter (inches from center hex bolt to center of torque wrench square shaft.
C = Desired torque at end of extrusion
D = Setting for accuracy within + or - 6%.
Here is a typical problem. You have an adapter that adds 10.0 inches to a torque wrench
length (dimension B) What should the setting be to obtain 320 ft. lbs. of torque at the end of the
adapter.
A = 22.57 inches (length from adapter mounting point torque wrench to center of grip / handle)
B = 10.0 inches (Length from adapter mounting point of torque wrench to center of hex slot).
C = 320 ft. lbs. torque (desired torque at end of extension).
D = Unknown (setting you need to set torque wrench to = 320 ft. lbs for accuracy).
(A) (22.57) (22.57)
C
= ------------------- or 320 ----------------------- = 320 ------------------ = 320 X 222 ft. lbs.
(A + B) (22.57 + 10.0) (32.57)
Your Answer (D) is a setting of 222 ft. lbs. on the torque wrench will give 320 ft. lbs. of torque at the
bolt. By using the above formula an accuracy of + or - 6 % of the desired torque will result at the end
of the adapter due to length change during grip adjustment.