Torque Wrench

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Battenkiller

Minister of Fire
Nov 26, 2009
3,741
Just Outside the Blue Line
Anybody know of an inexpensive but accurate torque wrench? I'm tired of worrying about over-tightening or under-tightening.
 
We tried those electric ones at work a few years ago, ending up throwing them all out after a year or so. Ate up batteries constantly and in the end they simply failed. Wouldn't read correctly, and we couldn't get them calibrated. Snap On denied the warranty.

Our cal shop preferred us to order Craftsman, Armstrong or CDI... The Snap On/Matco wasn't too bad, but they are $$ for what they are.

Now bear in mind they deal with thousands of various torque devices, so I'd say they have a general idea of what is good and what isn't. Point is expensive doesn't mean quality in this case.

I remember one order we had several new torque wrenches come in. I think I had 5 3/8" drive torque wrenches from Matco and 3 from Snap On.

I had to send back 3 of the Matco ones and 2 of the Snap On because they couldn't be calibrated... right out of the box! They weren't even close to being correct and couldn't be adjusted. Get the low end good and the high end was way off.
The worse part of it was the Snap On ones were send from warranty on another other... the 5 we had ordered, only 2 were good, and then the 3 new ones they sent, only 1 was good out of that!

Pretty bad when a $300-400 unit is junk but the $60 Craftsman is fine right out of the box!


At home most of what I'm working on just requires common sense and I guess a "calibrated" arm. I'll torque down wheel lugs, head studs, some differential and transmission parts. I have enough torque wrenches to do everything from pinion bearing preload to a big rigs lug nuts though.
 
I have a harbor freight click type. Not sure how accurate it is, but has to be better than the old beam style. I paid ten bucks for it.
 
I'd bet on the beam type being as or more accurate. I still use mine even though I've got several real high dollar fancy ones. A lot of the tool guys, ie MAC Snap On etc have gauges on their trucks to calibrate them. Might be worth checking if you see a truck around. A C
 
Go on Epay and buy a used quality mfg one (Mac, Snap-On, Proto Matco) and send it out for calibration.
 
I have a cheap clicker wrench kind of like the Harbor Freight ones that I got at a swap meet. Took it in to the metrology lab at work and it was right at 2 ft/lbs off.
 
wkpoor said:
Go on Epay and buy a used quality mfg one (Mac, Snap-On, Proto Matco) and send it out for calibration.
Click to expand...

+1. I can't tell you how many fubar'd jobs I've seen which resulted from people trusting something that really wasn't as it claimed.

In general, a lot of times people get themselves in trouble w/ or w/out a torque wrench for using a tool that is too big for a job. Just because someone has a 1/2 in drive socket that goes down to 10mm doesn't mean that they should use that 1/2 in drive ratchet for tightening a 10mm bolt. This large tool makes it very easy to over tighten.

Along those lines, even if a torque wrench is used there are right and wrong ways of using them. Just because a torque wrench is stated as having a range of say 25 ftlbs to 250 ftlbs, doesn't mean it's a good idea using it to tighten something at 25 ft lbs. Even if the tool itself is accurate, it is often times difficult to use it accurately! If there are inaccuracies, they will really become apparent in the low range of a torque wrench's range where a long handle can make it very easy to over torque something as many will feel quite vague here and there is less room for error.

Additionally, how you treat a nut going on a stud or a bolt will also change what torque it should be installed to. For example, if using moly lube these (referenced below w/ a link since it's blown up large) head studs get the nut torqued to 80ftlbs, but if you use 30wt motor oil, you need to torque to 120 ftlbs! That is a HUGE range based on a seemingly very small difference on brand new parts! Now try applying torque settings to bolts other than very important internal engine components and slight corrosion / slightly damaged threads will make the original specs obsolete.

http://www.enginemachineservice.com/2074202spec.jpg



pen
 
Battenkiller said:
Anybody know of an inexpensive but accurate torque wrench? I'm tired of worrying about over-tightening or under-tightening.
Click to expand...

More info needed:

Over/under-tightening bolts/screws for what?

What range do you need?
 
a) I have a harborfreight one, its certainly "good enough" I am not assembling SUBSAFE joints, just putting the oil plug back in the car (or similar jobs), I had also read a test on them and a few other brands, pretty much all the tested ones were within a few percent, no torque wrenches were way out. This is what I have: http://www.harborfreight.com/1-2-half-inch-drive-click-stop-torque-wrench-239.html

b) Pen - YOU GOT IT! There are so many other critical variables. For an oil drain plug, if there is oil on the threads or if they are dry has a ridiculous effect on how much torque is actually being delivered. Again, this is why "good enough" is, for me, more than good enough.

c) a lot of this requires common sense. A lot of the clicky wrenches (regardless of brand) suggest you click them a few times to lube the clicker thing first. Also, reading the reviews there are people who wanted 15 ft lbs then say it never clicked than their pneumatic torque wrenches couldnt get it off, so it was about 250 ftlbs. Well if you are stupid enough to over torque something to that extreme, I bet the thing did click, and you just didnt notice it. operator error

d) clicky torque wrenches, you should leave them set at just above zero. you want a little tension on the spring, but very little. Leaving them cranked way up could be a problem as the spring might not relax back properly. I use my pretty infrequently so I make sure to follow this.. If you use it all the time, maybe its not a concern. it was cheap insurance.
 
TreePointer said:
Battenkiller said:
Anybody know of an inexpensive but accurate torque wrench? I'm tired of worrying about over-tightening or under-tightening.
Click to expand...

More info needed:

Over/under-tightening bolts/screws for what?

What range do you need?
Click to expand...

Over/undertightening anything that has torque specs, I guess. Seems I'll need at least a couple of them with a broad overlap in ranges.

Pen, that's a bunch of great info that I hadn't considered but makes perfect sense. Especially the parts about choice of lube and condition of threads. I suspected there might be differences, but not by that much.

I think I'll start out with a couple of the Craftsman ones and be on the lookout for good used ones on EBay. Seems the pro ones hold their value well, but that makes them still pretty pricey for my meager needs. If I was gonna change a head gasket I would probably want a pro tool, but spending $300 so I don't overtighten a $26 brake rotor (typical stuff I do) doesn't seem necessary for my skills at the present.
 
Some examples:

John Deere 4600 tractor calls for 114 and 177 ft-lbs on the lug nuts and wheel bolts, respectively. For that I use a Precision Instruments "Split Beam" torque wrench, 1/2" drive, 40-250 ft-lbs. It has a 11 degree flex head that comes in handy.

Lots of other bolts get torqued with an old school Craftsman beam torque wrench, 3/8" drive, 0-75 ft-lbs.

I torque chainsaw screws and bolts with a Craftsman Craftsman Microtork Torque Wrench, 3/8" drive, 25-250 in-lbs

I use a Wheeler FAT Wrench (10-65 in-lbs) to mount rifle scopes, but I don't like it's precision so much.

The screwdriver and T-handle type torque wrenches come in handy when you are working on smaller bolts and screws.
 
Working on the lfight line we torqued the same nuts and bolts so many times we developed "calibrated wrists". For the common ones most of us quit lugging a torque wrench around. Every once in a while we would do a torque check later with a clicker and I don't ever remember a nut or bolt being found outside of spec. Walk down the line at night and you would here guys going "click click" "click click". By the time I left we had logged fifty thousand flying hours without a single maintenance related crash. And had a box full of shiny torque wrenches.

I calibrate my two clickers with my beam model. And sometimes even use the things. Not real often though.
 
If we got caught doing that where I work you would be in some HOT water!

For most people with some mechanical skill it's fine to use the "calibrated" arm, but I have worked with some guys that couldn't tell the difference between the flat head screwdriver and a framing hammer.

Plus, not to mention some of the items we work on are expensive. The AIM-120Cs used to be $1 million each. They are about 1/2 that now though, but the newer D is close to it.
 
NATE379 said:
If we got caught doing that where I work you would be in some HOT water!

For most people with some mechanical skill it's fine to use the "calibrated" arm, but I have worked with some guys that couldn't tell the difference between the flat head screwdriver and a framing hammer.

Plus, not to mention some of the items we work on are expensive. The AIM-120Cs used to be $1 million each. They are about 1/2 that now though, but the newer D is close to it.
Click to expand...

Stuff like the nut holding on the rotor head and drive shaft bolts were exceptions. :lol:

Every time I would see a episode of MASH where they mentioned "meatball surgery" I would laugh and say "Been there.".
 
... You guys use a torque wrench for oil drain plugs?
I just tighten it down until it doesn't tighten anymore... with a 3/8" drive. :|
For the oil filter I just snug it, then give it a little twist more.

I hate getting my car back after someone changes the filter... I can't get the damned thing off. Same with tire lug nuts. They impact them on to 151351ft/lbs. I tighten them to the recommended 100ft/lbs (this I actually do use a torque wrench for, in 2 stages).

I remember when I was changing my wheel bearing, I was going to all the auto stores, and rental shops in the area trying to find a shop that rented out a torque wrench that could do 290ft/lbs. I have never had to go that high before, so I had no need to buy one. and auto stores the rental is free... but even tool rental shops didn't have one. Most had 200, some 250...
I ended up just getting a 250 from Autozone, then using a breaker bar to crank it down a bit more after seating it.

P.S.
I use a craftsman 1/2" and 3/8" clicky type. Work nice. I was always told to take the tension off the spring by setting it to 0 when you're done using it. I don't know if it's a myth or not, but it makes sense.
 
Yes, clicker wrenches go to lowest setting when stored.

Also before use set to 50% torque and cycle it 3-5 times (make it click)

If your wondering I used to manage about 3 million in tools/equipment, plus I had a decent setup at home as well... and a certificate on the wall as an auto tech, currently working on one as a diesel tech too.
 
Years ago I got some help from a co-worker familiar with engine rebuilding. It was my first car and engine rebuild. I had a beam type wrench and was talking with the guy and he offered to bring his clicker over and "supervise" the assembly. We set the crankshaft and began tightening the main caps with his wrench. We went in steps as recomended. He set the wrench for the correct torque on the first step and started tightening. Tighter and tighter until the bolt snapped. He looked at me very surprised and wondered why the wrench never clicked. We got the broken bolt out, got a replacement and finished assembling the engine with my Craftsman beam type wrench. That was in 1982 and I still use the same wrench to this day.

Clickers are more accurate, faster, and easier to use but they must be turned back to zero torque after use and must be stored properly to prevent problems.
Beam type wrenches are adequete for the average guy and even good enough for a backyard mechanic. I have used mine to assemble at least a dozen engines from a 4 cyl. Subaru up to a street/strip 355 SBC without a problem.
I would suggest a 1/4 or 3/8" drive clicker and a 1/2" beam type for the bigger jobs.

Most newer engines bolt torques require an angle gauge as well.
 
BrotherBart said:
Working on the lfight line we torqued the same nuts and bolts so many times we developed "calibrated wrists".
Click to expand...

We called it "AQ (my rate) calibrated elbow". :lol:
 
NATE379 said:
If we got caught doing that where I work you would be in some HOT water!

For most people with some mechanical skill it's fine to use the "calibrated" arm, but I have worked with some guys that couldn't tell the difference between the flat head screwdriver and a framing hammer.

Plus, not to mention some of the items we work on are expensive. The AIM-120Cs used to be $1 million each. They are about 1/2 that now though, but the newer D is close to it.
Click to expand...
Business aircraft are getting up there too. Over 50mil is pretty common and the BBJ is probably pushing 100mil ( we have one of those in our fleet). Use of torque wrench is pretty much common sense. You know as an experiences mech whats torque critical and whats not. More then not people tend to over torque fasteners more then under.
 
kettensäge said:
Years ago I got some help from a co-worker familiar with engine rebuilding. It was my first car and engine rebuild. I had a beam type wrench and was talking with the guy and he offered to bring his clicker over and "supervise" the assembly. We set the crankshaft and began tightening the main caps with his wrench. We went in steps as recomended. He set the wrench for the correct torque on the first step and started tightening. Tighter and tighter until the bolt snapped. He looked at me very surprised and wondered why the wrench never clicked. We got the broken bolt out, got a replacement and finished assembling the engine with my Craftsman beam type wrench. That was in 1982 and I still use the same wrench to this day.

Clickers are more accurate, faster, and easier to use but they must be turned back to zero torque after use and must be stored properly to prevent problems.
Beam type wrenches are adequete for the average guy and even good enough for a backyard mechanic. I have used mine to assemble at least a dozen engines from a 4 cyl. Subaru up to a street/strip 355 SBC without a problem.
I would suggest a 1/4 or 3/8" drive clicker and a 1/2" beam type for the bigger jobs.

Most newer engines bolt torques require an angle gauge as well.
Click to expand...

I had a decent beam-type torque wrench many moons ago, but I never used the thing and damn if I know where it went. I think it was a SK brand, which were pretty good tools at the time. I had acquired a fair amount of tools way back before I got married, back when I actually believed I'd someday do a complete rebuild on a nice small-block Chevy engine. I kinda lost interest in working on cars after all the electronic ignition and emission stuff came out and you needed to be a rocket scientist to understand how to tune the damn thing. I would love to go back to the days when you opened the hood and it was all just there in front of you, easy to access and disassemble. Nowadays I look inside an engine compartment and it looks like a mass of robot intestines. Close the hood, call the tow service.

Like many of my age, I go back to carbs, points, and a dwell meter and a timing light (don't know where they are either) to set the dwell time and spark advance. Since then my mechanical abilities only extend to brakes, plugs, wires, batteries, lights, oil changes, and the occasional cobbled up exhaust parts MIG welded together. I suppose it's never too late to get back into the game, though. Heck, I just bought a code reader, so at least I might have an idea where to start.

So far, I used it on Lady BK's Jetta when she had a flashing trouble code pop up. PO301 told me "Misfire on cyl. 1", so I bought plugs and wires and started there. Number 1 plug (originals I discovered, with with 120K on the car) had a honking huge gap due to a gouged out ground electrode. Changed the plugs, reset the code, ran it again, no codes found... returned the $80 wires to Advanced Auto and got away with a $15 fix. Kewl. If I had that thing towed to the VW dealership they would have told me it needed $1000 worth of work, guaranteed.
 
At the papermill I used to work at, there was a felt tension assembly on one of the papermachines that would fail frequently. The machine ran 1200 feet per minute and when it lost tension, the fabric would get trashed which required a new fabric at $12,000 plus 8 to 12 hours of no production. I was asked to look at it and the assembly was snapping 1" bolts due to sidewards loading. Usually the failures would occur at night or on weekends so I didnt see the normal fix. When I finally saw the fix it was one man with a 3' breaker bar in an awkward location tightening the bolts. I had them get a torque wrench (with a mulitiplier) and they tightened the bolts to the proper tension (I think it was 600 ft lbs but would have to look it up). No problems after that. Once you get on the big bolts you need a torque wrench as no many folks have "calibrated arms" for hundred of foot pounds.
 
peakbagger said:
Once you get on the big bolts you need a torque wrench as no many folks have "calibrated arms" for hundred of foot pounds.
Click to expand...

Yeah. We used the big torque wrench and multiplier for things like the Jesus nut that holds on the rotor head, called that because that is what the pilot says if it bounces off the windshield in flight, and the big nuts holding the foreward and aft transmissions in. The stuff I was talking about are the fasteners for the small transmissions and other stuff that you pull and re-install a dozen times a week.
 
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