inch lbs. torque wrench
Thanks ole4, I read that when reading the little manual that came with torque wrench and makes alot of sense. No sense in stretching spring and getting tool out of correct reading or torque setting . Hadn't used it yet but going to when i put billet rod in cause people have stressed the importance of the correct torque on a billet rods cap bolts.
Copied from Hot Rod testing.
Torque Wrench Testing - Shop Tools - Car Craft Magazine
We ran the torque adapter through five consecutive applications of 70 lb-ft of torque to watch it hit within 0.10 of a lb-ft twice and actually hit exactly 70 lb-ft on one occasion. The average of the five tests was an amazing 70.1 lb-ft. The unit offers a digital readout and warning lights, and it even emits a progressive electronic beep when nearing the pre-selected torque.
Next, Chauvie suggested an even more interesting test. He offered to keep our Harbor Freight 1⁄2-inch clicker wrench and test it every 30 days for two months while keeping the wrench loaded at 70 lb-ft. He said the problem with clicker torque wrenches is, when the mechanic fails to return the preload to its lowest setting after each use, the tool begins to lose accuracy. Chauvie says the longer the wrench is loaded, the less accurate it will become. He has since reported on the torque wrench’s performance at 30 days and 60 days, and we’ve included a graph to show the results (page 30). This inaccuracy occurs because the internal spring loses its tension, allowing the wrench to break away (click) at a lower torque value. Chauvie says this is a common problem for all types of clicker torque wrenches. The point here is that you should always return your clicker torque wrench to the base setting before storing the wrench. This simple step will maintain the wrench’s accuracy for years instead of mere months.
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Torque Wrench Testing - Shop Tools - Car Craft Magazine
We ran the torque adapter through five consecutive applications of 70 lb-ft of torque to watch it hit within 0.10 of a lb-ft twice and actually hit exactly 70 lb-ft on one occasion. The average of the five tests was an amazing 70.1 lb-ft. The unit offers a digital readout and warning lights, and it even emits a progressive electronic beep when nearing the pre-selected torque.
Next, Chauvie suggested an even more interesting test. He offered to keep our Harbor Freight 1⁄2-inch clicker wrench and test it every 30 days for two months while keeping the wrench loaded at 70 lb-ft. He said the problem with clicker torque wrenches is, when the mechanic fails to return the preload to its lowest setting after each use, the tool begins to lose accuracy. Chauvie says the longer the wrench is loaded, the less accurate it will become. He has since reported on the torque wrench’s performance at 30 days and 60 days, and we’ve included a graph to show the results (page 30). This inaccuracy occurs because the internal spring loses its tension, allowing the wrench to break away (click) at a lower torque value. Chauvie says this is a common problem for all types of clicker torque wrenches. The point here is that you should always return your clicker torque wrench to the base setting before storing the wrench. This simple step will maintain the wrench’s accuracy for years instead of mere months.
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Interesting thread. Being a retired Navy Jet Mechanic with 26 years working on rngines and helos the subject of rolling back the torque wrench always came up. We were always taught to roll back the setting. While in the Navy the Army did an extensive testing of torque wrenches to resolve this argument to roll back or not. At the conclusion of the tests there was less then 1% loss in accuracy. But I prefer better safe then sorry approach. Also know that anytime a torque spec is given with a range of say 45-55 inch pounds always go for the middle value.
I worked "B&D" in a Navy Calibration lab for a couple of years. Torque wrench calibration standards were every 3 months, then moved to six month calibration schedules. They were seldom out of calibration, so we verified. Failures were red tagged and returned to the USMC/Navy squadrons who tossed them in the trash. They don't go out of calibration unless you drop them from an aircraft wing. 
