I keep a torque wrench in the trunk of my car. Unfortunately, I’ve stored the wrench loaded all this time. The wrench was actually set and locked at 78 lbf.ft. The wrench is a mechanical click type. By storing it loaded, the pressure on the spring will eventually weaken it. Resulting in an inaccurate torque reading. It’ll click before reaching the desired torque setting. (Check out this article from www.hotrod.com)
I did some searching and stumbled upon digital torque adapters. Digital torque adapters measure the torque applied to a nut/bolt and displays the pressure applied on a digital screen. This can convert any socket wrench into a torque wrench. It will not prevent over torquing, but will signal (via audio and/or visual markers) when the target torque setting is reached.
Another feature of digital torque adapters allows the user to test the accuracy of their torque wrench. By knowing how far off the wrench is reading, the user should be able to fine tune the wrench.
I picked up a Pittsburgh Professional Digital Torque Adapter a my local Harbor Freight Tools brick and mortar store. After a 20% discount (via email coupon), the total only came out to $26.39. Harbor Freight always gets knocks on the quality of their goods (rather, lack of quality), but this device is fairly accurate (check out this article from www.hotrod.com).
I tested the two torque wrenches that I own. One is a Craftsman and the other is a Gorilla Automotive wrench (the one improperly stored). The Craftsman wrench was stored properly. In fact, the only way for it to fit in its storage case is when the torque setting is set at the minimum value (~ 20 lbf.ft). The Gorilla Automotive is smaller in size and can fit in its case on any setting. The Craftsman pretty much matched the digital torque adapter… maybe off by 0.1 lbf.ft. The Gorilla Automotive was off by 4-5 lbf.ft… it clicked before reaching the desired torque setting. I did weaken the spring on the wrench.
It took awhile, but I was able to adjust the Gorilla Automotive wrench to within 0.5-0.8 lbf.ft. I only use this for my lug nuts and that’s accurate enough for me. For added security, I’ll store the digital torque adapter in the trunk and use it whenever I use the Gorilla Automotive wrench. Big props to dail2fast on YouTube. He did a great review on the Pittsburgh Pro Digital Torque Adaptor (link here) and a guide in calibrating a torque wrench (link here).