Torque Wrenches?

[Lee]

I've decided to do more mechanical stuff myself...mainly on my motorcycle, but not limited to that.  I'm more willing now to possibly destroy any of my stuff that isn't covered by warranty.   I've got a cheap Stanley beam wrench that I bought long ago. I'm not sure if it ever really worked well, although I don't recall breaking anything or having any parts fly off.  I'm thinking that a poorly torqued motorcycle part is not a good thing though. Browsing the net seems to indicate that there are only two choices 1) $29.95 or 2) $295. 
Is there a decent wrench out there that is somewhere in the middle of that price range (or lower) - but nearer to the top of the accuracy and quality range?   

[TechMan]

I have 2 of the Husky wrenches from Home Depot and they seem to do a decent job.

[Jim147]

You might check KD Tools. I've used a lot of their specialized tools over the years without a problem.

http://www.kd-tools.com/

jim

[Nick1911]

I have 2 of the Husky wrenches from Home Depot and they seem to do a decent job.

My 1/2 incher is a Huskey.  My 3/8th and 1/4 inch ones are $9.99 from harbor freight.  I've never done any real testing to see if they are accurate, but I have used them a lot over the past two years on engines, suspension components, etc.  I've yet to have anything come loose, and I've yet to break any fasteners.

[CNYCacher]

I've decided to do more mechanical stuff myself...mainly on my motorcycle, but not limited to that.  I'm more willing now to possibly destroy any of my stuff that isn't covered by warranty.   I've got a cheap Stanley beam wrench that I bought long ago. I'm not sure if it ever really worked well, although I don't recall breaking anything or having any parts fly off.  I'm thinking that a poorly torqued motorcycle part is not a good thing though. Browsing the net seems to indicate that there are only two choices 1) $29.95 or 2) $295. 
Is there a decent wrench out there that is somewhere in the middle of that price range (or lower) - but nearer to the top of the accuracy and quality range?   

With a fish scale or a known weight it is easy to test them.  Clamp the square drive into a bench vise and position the handle so that it is parallel to the floor, and supported by the ratchet action.  Attach a known weight to the handle exactly 12 inches from the axis of rotation (1 foot).  The wrench should click out at as many foot-lbs as the known weight.  No more, no less, or at least within a reasonable margin of error.  Test with various weights to cover the spectrum that the tool claims to measure.

If the handle is not 12 inches long, then go 6 inches and use double the weight.  Or go 8 inches and use half again more weight.  You could also go 2 feet and use half the weight.


An example:  Set the torque wrench to 20 ft-lbs.  Hang 20 lbs off the handle, one foot from the axis.  Try different settings above and below 20 lbs to make sure it works as expected (below 20 should all click.  above 20 should not click).  Repeat for different weights to cover the spectrum of your tool.

[bedlamite]

http://www.sears.com/shc/s/p_10153_12605_00944594000P?sid=IDx20070921x00003a&ci_src=14110944&ci_sku=00944594000P

[Lee]

Great info- Thank you!

[Hawkmoon]

These days they are ALL made in China, and probably all in the same factory. For general automotive (and motorcycle) work, the $29.95 (or $19.95, or $9.95) wrench is just fine. If you read most automotive specs, they give a range of at least 10 percent for torques. So if your wrench is off by 5 percent (which would be a lot for aerospace work) -- who cares? What's more important than the actual value (as long as you're not torquing a 50 ft-lb bolt to 150 ft-lbs) is that all fasteners in a group are tightened to the same value. And the cheapie wrenches are just fine for that.

[CNYCacher]

What's more important than the actual value . . . is that all fasteners in a group are tightened to the same value.

QFT.

Also, it bears mentioning that torque itself isn't all that important, it is merely the easiest way for us to gauge the tension on the bolt.  Bolt tension is what is important to the part being held down.

In theory, two identical bolts threaded into two identical holes and tightened to the same torque will have the same tension and clamping force.
In practice, making sure your bolts and holes are clean and free of debris, that the threads (inner and outer) are clear of debris and undamaged will probably do as much for keeping your parts adequately and evenly held together as would testing the accuracy of your wrench.

[Nick1911]

QFT.

Also, it bears mentioning that torque itself isn't all that important, it is merely the easiest way for us to gauge the tension on the bolt.  Bolt tension is what is important to the part being held down.

In theory, two identical bolts threaded into two identical holes and tightened to the same torque will have the same tension and clamping force.
In practice, making sure your bolts and holes are clean and free of debris, that the threads (inner and outer) are clear of debris and undamaged will probably do as much for keeping your parts adequately and evenly held together as would testing the accuracy of your wrench.

Which is why for critical automotive applications, many manufacturers have gone to Torque-To-Yield bolts.  The specs for these bolts will be something like "Torque to 150ft/lbs, then tighten an additional 90 degrees."

Apparently this actually stresses the bolt beyond the elastic phase, and into plastic deformation.  The net effect is two fold: firstly, it acheives more consistent clamping force.  Secondly, it means you have to buy new bolt every time you take them out.  One use only.   

[never_retreat]

Biggest thing is to turn them back to zero or the lowest setting when you are not using it.
Leaving it cranked to a 100 lbs is not good for them.

I have a 3/8 drive snap on that goes 0-100 I believe. I use it mostly on the aluminum engines and parts on the jet skis and snowmobiles.
100 is to low for things like head bolts so I have had to borrow a bigger one from time to time. you just need to look at the parts also, if its just two pieces of steel without any type of seal just make it two grunt tight and you should be good.

[never_retreat]

Remember the basics.
Righty tighty
Lefty loosey
Tights tight
Too tights broke

[TechMan]

http://www.sears.com/shc/s/p_10153_12605_00944594000P?sid=IDx20070921x00003a&ci_src=14110944&ci_sku=00944594000P

I have a Sears but it is inch pounds and I user it for my spark plugs on my John Deere.

[Monkeyleg]

I have the same design Craftsman torque wrench, but it's 1/2" drive, 20-150 ft. pounds, and much better quality than what's made now. I bought it for $75 in the 1980's. IIRC, it was made in the US, too.

[Nick1911]

Biggest thing is to turn them back to zero or the lowest setting when you are not using it.
Leaving it cranked to a 100 lbs is not good for them.

I have never heard this.  May I ask what the rational is?

[TechMan]

Biggest thing is to turn them back to zero or the lowest setting when you are not using it.
Leaving it cranked to a 100 lbs is not good for them.

I have a 3/8 drive snap on that goes 0-100 I believe. I use it mostly on the aluminum engines and parts on the jet skis and snowmobiles.
100 is to low for things like head bolts so I have had to borrow a bigger one from time to time. you just need to look at the parts also, if its just two pieces of steel without any type of seal just make it two grunt tight and you should be good.

I do this too.

[Hawkmoon]

I have never heard this.  May I ask what the rational is?

Not sure why, but the instructions that came packed with one of my older click-stop torque wrenches included this caution. The newer ones don't have any instructions. (I carry one in the back of each Jeep, for lug nuts if changing a tire away from home. Unevenly torqued lug nuts can cause warped brake rotors.)

[Nick1911]

Not sure why, but the instructions that came packed with one of my older click-stop torque wrenches included this caution. The newer ones don't have any instructions. (I carry one in the back of each Jeep, for lug nuts if changing a tire away from home. Unevenly torqued lug nuts can cause warped brake rotors.)

Huh, weird.  I'll have to research that.  My guess would be that they seek to avoid constant spring tension, thinking it will weaken the spring.  But, I think I read about how that was not really the case, at least for magazine springs.

[Boomhauer]

Huh, weird.  I'll have to research that.  My guess would be that they seek to avoid constant spring tension, thinking it will weaken the spring.  But, I think I read about how that was not really the case, at least for magazine springs.

That's generally true for coil springs, or at least the type of coil spring used for mag springs.

Flat springs and I believe some types of coil springs (and by type, I mean composition) can have issues with constant spring tension, IIRC. I have no clue what type of springs are in a torque wrench. I've got a torque wrench around here. Somewhere. Think it's a 3/8" drive. I never use it, I tighten stuff by feel.

Unevenly torqued lug nuts can cause warped brake rotors.)

Never had a problem torquing lug nuts with a plain breaker bar. Have had plenty of problems with other people f***ing up lugnuts and studs by thinking they are NASCAR pit crewmembers when they get their hands on the impact guns...

In fact, I have very, very few problems with threaded things of all types when I install them (and later remove them). Something about attention to detail and knowing the proper feel of tightening stuff. Now, if someone else did the installing or removing, then I've figured out there is a 95% chance it's going to be f'ed up in some way or form. 

[zahc]

What's more important than the actual value (as long as you're not torquing a 50 ft-lb bolt to 150 ft-lbs) is that all fasteners in a group are tightened to the same value.

Quoted again for truth. Also, never trust a torque wrench, or published torque specs. Always use common sense and feel to sanity check them and the torque specs you are following. I used to follow my Honda's owner's manual torque specs with a good quality Craftsman torque wrench. I thought I was doing the right thing but after stripping out my oil filter cover screws, pinching my triple clamps shut, and bending my chain adjuster due to insufficiently but 'correctly' torqued rear axle I threw the torque wrench in the bottom of the tool box and started tightening things as tight as they need to be.

[Monkeyleg]

Some parts are such that you can get away with "feeling" the right amount of torque. Others, like cylinder heads, aren't as forgiving, especially aluminum cylinder heads as are found on bikes.

[sanglant]

if you go cheap, i have no idea if this is true on the costly ones. remember not to go lighter then the minimum, you can feel/hear rattling when your getting close. the wrench will fall apart. my 20 dollar wonder is still working fine after 5 years.

and the breaker bars are a good idea. handy things. and nicely weighted

[French G.]

Find a used Sturtevant flat beam. All the click types I've used are Snap-on, not cheap. New Sturtevant, not cheap either.

If any instructions give you a torque and specify dry torque, an idiot wrote them. Lube on the bearing surface and threads, otherwise you are measuring friction and not bolt stretch.

[Hawkmoon]

By all means, lube the threads and head ... but then you have to reduce the torque by 15% to 25%. The reduction isn't a fixed percentage -- it varies depending on bolt diameter and thread pitch. The Nutty Company used to have a chart that gave all that info, lemme see if it's still on-line ...

... yeppers: http://www.nutty.com/pdfcharts/torque_chart.pdf

[French G.]

Yes, get the corect torque. A lubed torque is just less variable than a dry one. Critical things you can access both sides of, like a connecting rod bolt, you just torque and measure with a mic until you get the right bolt stretch.