Since I'm about to re-torque my heads I started thinking and reading about torque wrenches. What I have realized is that I have not taken care of mine in the manner that they require to be accurate. I have 6 for different things Ive done requiring different types. I set up a Grade 8 test bolt lubricated with copper anti seize (for consistent pulls) in a vice and used a beam style to compare against the of the others. One from HF went rite to the trash, I could not even get it to work and failed at trying to recalibrate it. One I bought for the 9" rear end nut (STORM) was rite on but is long and cumbersome, the others are for inch lbs. or dial type so , I ordered one Snap on clicker type suited for my head bolts (It was listed as one of the top five in its category for 2017), and one (Tekton) clicker for other stuff, (it was also listed as one of the top five for 2017). I started this thread not to teach (I don't know enough to do that) but rather to bring up the subject for the others like myself that don't know all we should about this tool, that I myself treated just as if it were a combination wrench. Maybe some of the pros on here can share the proper care and maintenance needed for these tools, and what to look for when purchasing a new one. So much to learn, so little time

 

Proper storage is one important thing you need to know about clicker type torque wrenches. I have 3 Proto clicker torque wrenches, two require that they are backed completely off when not in use and the third one is supposed to be stored at 20% of max torque. I am sure every brand may be different. I have sent mine off several times to be recalibrated. They are overdue now, but I haven't used them very much. I have installed a number of heads over the years with a beam type torque wrench, the clicker type sure makes that job easier.
Mark

 

One important thing is that they don't get dropped and banged around, say knocked off a workbench down to a concrete floor. That will bugger up the calibration enough to matter.

What's crucial is that certain things like heads, intakes and manifolds, etc are tightened evenly, that the mating surfaces have been machined flat or dressed up to be true, and use new, good quality gaskets if required. I have good success being meticulous and following the "rules". If I half *** it, not so much. I really dislike doing complicated stuff over again, especially anything that leaks fluids, compression, or fuel. I'm not so concerned that a torque wrench isn't perfectly accurate to +/- 0.005 ft lbs, but the fasteners all need to be the same torque. A torque wrench will do that for me.

It's also important that the proper tightening sequence is followed to draw up the pieces evenly, say in a criss-cross pattern or, whatever the manual shows.

Usually the manual will also indicate something like to tighten in three progressively higher torque steps - 20 ft lbs, 60 ft lbs final torque 120 ft lbs. I like to extend that out further to four or five steps. Never use a torque wrench to loosen fasteners or extend it past the "click". They are really only used properly for torque. They aren't quite as accurate when first used "cold". Don't jerk on the handle, nice easy draw, let it work for you.

They are most accurate in the midrange of their rated scale, so use the approriate size wrench. This is a valid excuse to buy more tools. A 150 foot pound wrench won't be as consistent set to 5 foot pounds.

Pay attention in the manual to any retorques required. Usually a heat/cooling cycle or two for example with cylinder heads will tend to cause fasteners to loosen up as parts settle in. Re-torque in the tightening direction to at least the minimum torque specified after a few hundred miles or when cold, or whatever the manual specifies. They'll settle in after a few iterations.

 

Jim, I have a couple of Snap-on Clicker types and when purchased new (years ago) from my dealer he instructed me to set them at their lowest torque setting when storing them. I have done that ever since. I have never read or been told different so that is what I continue to do with them.

Like always, a good post by you.

 

When I was in the USAF the torque wrenches, clicker type, had to be fully backed off, and stored at room temp? - They had the go to a precision measurement lab for recal once a year also if they were dropped they had to go back for recal
My elbow came with a lifetime calibration

 

Had a set of snap on wrenches and due to my excessive travelling with them the calibration tended to only stay within limits (aviation is 3%) (automotive is 5%.) for about 3 years. That's going in every year to be recertified. Now I have a new set of CDI (snap ons high precision) digital wrenches. They are suppose to be .1% accurate so testing them out to see how long they last in this industry. But Dave is right, click type torque wrenches require that you put them to the lowest setting otherwise you will compress that spring inside them and they will be no longer accurate.

 

Jim, how were you testing them with that bolt? I don't understand how you were doing that.

I got a good deal on a digital TW, a great thing when you have 48 head bolts to tighten in 3 stages. It has a yellow LED that lights up at 90% of setting and it beeps at the setpoint. Very handy when you're laying across the fender and can't see the dial.

 

That is what I always thought until I bought a new Proto torque wrench a few years ago. It specifically says in the manual that when not in use it must be set at 20% of the maximum torque. It is an 80ftlb wrench, so I store it at 16ftlbs. My 2 older Proto wrenches do say to back them all the way off. So, I would read the instructions that come with your specific wrench as they are not all the same.
Mark

 

Ross, I believe he is torqueing the bolt with his beam type and adjusting his clicker wrenches until they stop clicking and reading the torque on the barrel.
Mark

 

I agree with what's already been said. I've not heard of storing at a particular setting (other than within 10% of the lowest setting) but I've not seen everything, so...

A couple extra thoughts -

Beam type wrenches normally remain accurate and have the ability of being user adjustable (just tweak the needle to center before using.) They are the most reliable mechanical wrench in the 'repeatable' sense. Don't abuse them, they are a bit temperature sensitive but I doubt no more than any other types excepting strain gauge types. Be aware of the 'parallax' issue - viewing from an angle other than 90° will cause issues. One thing to keep in mind is beam type wrenches trade reliability for precision - scales are typically in 5 - 10 inch or foot lb. increments.

Electronic or 'strain gauge' torque wrenches are electronically simple and pretty reliable tools. I occasionally use the one HB sells and have found it reliably accurate. Even if you're doubtful buy and send one in for calibration (they ship with a certificate, for whatever that's worth.) You'll still come out money ahead. About the only maintenance it requires (other than not using it to keep your truck from rolling down the driveway) is to take the battery out over long periods of non-usage. I figured it was a kind of put up or shut-up situation so I torqued the rods and mains I tossed in my 215 last year and haven't had an issue. However, in the realm of self- protection, your mileage may vary. ;-)

Butting up two wrenches against each other by way of an adapter or torquing the same bolt is absolutely no way to 'check' a torque wrench. It just doesn't work that way. In the case of torquing a bolt then checking it with another wrench there is a amount of extra torque required in order to 'start' the fastener moving the second time. Also see:

When the wrench signals the setting, stop! I can't tell you how many times I witness guys I work with (professionals that should know better) click - click - click a fastener when torquing. Each time you apply more torque in order to make the wrench signal again you're applying more torque in order to get the fastener moving again. If done the same on each fastener they may come out equally torqued but definitely not to spec.

How often to check calibration and where to have it done? Often used (professional) every 6 - 12 months. The higher the performance of what you build = more often. Where? MAC Tools (I used to be an owner/distributor. 1-800-MACTOOLS Not endorsing or advertising, just informing of one possibility) will calibrate anything but Snap-On. Also check the yellow pages in your area (what the heck are those?)

 

This thread has perfect timing. I just asked my so to ask his buddy to borrow his torque wrench. My wife says why don't you just buy one.

So, I am in the market. I need a wrench to tighten the head bolts when I replace the heads on my 54. There is a Harbor Freight 30 miles away, there is a small Sears store in town that sells tools and appliances and several parts stores one of which is Advance Auto. I wont be using them very often so what kind is the best kind for me, clicker, pointer or digital?

 

Hi Ross, I would use the clicker to say 50 lbs, then use the beam to see if 50 lbs would get it to move any more, then loosen the bolt and reverse the procedure, beam then clicker. I did this at 20, 50, 60 and 80Lbs. Not very scientific but it gave me an idea of where I was, since I read that the beam style were more of a constant??? I have a question. Is there a company that will re calibrate all brands, or are they proprietary and need to go back to there maker? EDIT Beav, I just saw the end of your post, which answered my question, thanks.

 

That's pretty scientific, but has one flaw. There are two types of friction coefficients....static and dynamic. When torquing, it is important to keep the wrench moving until the goal is reached. If you need to retorque, and it won't move, it may be because it is starting at static friction, which is higher than the dynamic number. Your only choice is to back it off a bit, and then approach it moving. The other thing to remember is to use the proper lubricant. A real torque spec always specifies the required lubricant.

I am overdue to get my torque wrench calibrated. Fortunately, I no longer torque the rod bolts on my racing stuff. The bolts give me a stretch number. I have a spanner with a dial gauge. So torque is not important in that case.
I know... LOL

 

Like most things tool related there is "good" "better" and "best". The cheap torque wrenches don't inspire a lot of confidence in the smoothness of operation, or even how well they will hold onto a socket or extension. Accuracy, who knows? I like click type wrenches for general use in the 50 to 150 foot pound range, made by someone like Craftsman. Since use is infrequent, buying the high dollar version doesn't make a lot of sense. May have to buy used these days, I dunno. But then there is the issue of calibration - do you trust the former owner to have taken care of his tools? The spring dial type seem well suited for lower torque fasteners into the inch pound range, 0-30 and thereabouts.

One area where a lot of folks seem to have problems is when using fasteners that call for cotter pins. Castellated nuts have a torque range. Depending on thread cut of the nut and bolt, the hole may not line up within the specified torque range. The idea is to torque within the range so the hole lines up, and insert a cotter pin. Simply trying a different nut, or adding a thin washer or two will do the trick, but oftentimes peeps will just reef the nut waaay past the max torque value in order to get things lined up. If you're going to use a torque wrench, learn to use it correctly. A lot of people who should know better are not clear at all on the torque wrench concept.

 

When I worked at the Caterpillar dealer they paid for our multi meters and torque wrenches to get calibrated quarterly. Cheaper than warranty work because of out of calibration tools.

I have 1/2" drive and 3/8" drive Snap-On torque wrenches that never needed adjustment in the 15 years I worked there. We got paperwork back with the tools but, I don't remember the tolerance or specifics of the tests. The original clear epoxy is still over the adjustment plugs or covers.

My Craftsman and Proto models got tossed. Never passed and too expensive to fix.

I quit back in 2004 but, even then Cat was going to a low torque starting point and final torque was turning the fastener a number of degrees. Usually on the larger fasteners.

Some tools can be cheap but, buy a quality torque wrench. Only exception is a beam type torque wrench. They are pretty accurate and stay accurate. Not so good in positions where you can't see the scale though.