My son is a pro mechanic and has a couple of Harbor Freight torque wrenches. He checked them against the shops Snapon wrenches when the truck came by.
The HF wrenches faired very well especially compared to the Snapons. For the less than 1/10th the cost of the Snapon they are a certainly usable for a home mechanic.
He's had his for a few years BTW.
Spec, he wouldnt have known his HF wrenches were ok if it werent for the Snap-on truck. Where is HF's truck?
The HF torque wrenches Ive taken to my Snap-on dealer have been spotty in terms of calibration. Some were within 5%, some were closer, a couple were 20% or more off. Ive brought in MAC torque wrenches also. One clicked off at 90 ft lbs when the wrench was set to 62 ft lbs.( Mazda had a head gasket campaign involving '79-'82 626s and B-Series Trucks). One is a MAC in-lb model I also own, and is on the ragged edge of 5% off, while my 30-year old Snap-on in lb models are right on the beam. And I used my Snap-ons day in and day out.
Tools didnt cost me money--they MADE me money. The better tools made me more with less down time and more accurate results. And I only had to buy them one time.
The point is no matter whose torque wrench you use verify the calibration.
As for anybody who thinks they have a calibrated arm, yes, I can get close from decades of doing this. But, not always. And from Day 1 I made it a point that if there was a spec for the bolt or nut, I torqued it to spec. When you personally have witnessed the aftermath of wheels coming off a car, or have to repair stripped valve cover bolts that the previous ALLEGED TECH tightened, you see the value in torquing.
Many times fasteners strip while torquing due to bolt or thread damage from prior over-torquing. And you can get into trouble real quick if you just blindly torque away and not feel threads ready to let go, or a bolt snap in half.
Which is how I got my 2 month old Snap on 1/2" electric impact wrench. The tech left wheels loose, 2 came off, wiped out the back of a Mazda RX-8...and blamed the tool. The dealer took it back, tested it, was just fine, and I bought it for 1/3 the cost of new. When I asked the...tech.. what happened, he told me the impact wrench failed. I asked him if his torque wrench failed at the same time. *Crickets* is all I got in return. He torques them all by hand now.