I just finished doing a routine service on my Deluxe, and as usual made sure to torque drain plugs, spark plugs, etc., to the proper specs. And also as usual I found myself wondering just how much to trust my wrenches (different ranges, Sears, Husky, Harbor Freight). Sure, I could send them to some tech lab to be tested for accuracy and consistency at regular intervals -- which I'm sure would cost more than the wrench did, so I don't.

I also just got around to looking at some magazines, including American Iron #315 (October 2014). The article on "Torque Wrench Tech" (page 34) was interesting, especially the part on "Testing Torque Wrenches". Here's a brief excerpt for those who don't have the magazine handy:

"...I take a simplier and less expensive approach to torque wrench testing by comparing wrenches to see if they provide the same torque indications. I begin by setting my 3/8" drive clicker torque wrench to the middle of the scale. Then I put a 12-point 7/16" socket on my beam torque wrench and use it to couple the two torque wrenches together as shown in the photo. You must use a 12-point socket because a 3/8" square drive will engage every third point in a 12-point socket. While watching the scale on the beam torque wrench, I slowly move the wrenches together. If I feel the click when the pointer on the beam wrench corresponds with the setting on the clicker wrench, the two wrenches are probably both accurate. I can repeat this process with other settings of the clicker wrench to check at one third and two thirds of the maximum range on the torque range of the clicker..."

I checked my wrenches and they all seem to read within close tolerance, so I feel a bit more confident in using them.

 

That's a good idea. Think I'll check mine too using that method.

It's most important to check what lube a specified torque setting is for and that the threads are clean of gunk like old thread locker or sealant. I usually rock the clicker twice twice when torquing down a bolt and never stop mid stroke. It takes more torque to get the bolt moving again and you can under torque the fitting.

 

I wonder how close my Harbor Freight torque wrenches are?

 

There are videos on youtube that shows a way to check them using weights. Just type in torque wrench calibration. I did this about a year ago and they were pretty close.

 

I could be wrong but I think if you buy quality wrenches then you shouldn't have to worry about them being out of spec. Most torque values have a range. If you set to middle of the range then even if your wrench is off a little it will still give you proper torque within the range. Obviously, if you are working on critical equipment such as aircraft engines then the wrenches need to be more precise and undergo routine accuracy checks.

 

One thing some people may forget is to always back the the snap type wrench off to within 20% of the lowest reading when finished using it (you can fill the spring unload) . Least that is what they say in owners manuals. However that probably is a good and accurate enough check. Harbour carries a lifetime warranty. I sort of did a similar eye ball check on my 150 1/2" Harbour locking it in the vice and using a rolled leather glove and the bathroom digital scale. Was good enough for me. As part of my apprenticeship years ago, I worked in calibration for 3 month in a Nuclear shipyard. We were required to calibrated foot lb Snap On dial torque wrenches to within 1/10 of a lb. We cut up and destroyed at least 1/2 of them. We actually rejected so many new ones, the company sent someone in to see what we were doing. Shortly after that, they farmed the calibration out to someone and they never had any more problems...

 

Even the best wrenches need to be calibrated when new out of the box. The better ones will be closer to spec, but you would be surprised how many still need to be calibrated. Once calibrated, the better tools will hold spec longer. I use KD Tools (made in USA) torque wrenches and one Sears Craftsman inch pounds torque wrench (China or some sh*t). Once they had their initial calibration, the KDs have held their spec. The Sears, not so much.

 

 

As one that rides a motorcycle AND flies a jet aircraft, I can tell you this with absolute certainty. I would rather an engine in my jet come apart at 35,000 feet, than for the engine on my motorcycle to come apart while I'm going down the road at 80 MPH, or a wheel come off, or any of those other "critical" things! LOL!

 

As one who has one come apart at FL350 and 30W I can tell you it weren't no picnic! But I know what you mean