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torgue wrench

5K views 17 replies 9 participants last post by  1bad18 
#1 ·
Is there a way a guy could check the calibration of a clicker style torque wrench?? :thumbup:
 
#2 ·
yes but you need an open end pointer style/ dial style torque wrench ( that is calibrated ) and 2 sockets that are the same size welded togther, then put the pointer wrench in a vice and set the clicker for 50 ft/lbs or so and then crank on it, if it reads 5o ft/lbs when it clicks, it's in calibration.
 
#5 ·
Sbchev, I agree I just don't see how a pointer type (I am assuming he means a beam type) wrench could even work if clamped in a vise, besides the possibility of damage to the wrench. Theoretically I suppose a dial type wrench may read correctly if clamped in a vise but I would not do that to any precision tool :pain: The simple and proper way to do this is to have it calibrated by a shop, check with a large service center or car dealer service shop to find where they have it done in your area. Even the local Sears here, at least some years back, would have any brand wrench calibrated for a small charge.
 
#6 ·
Thanks guy's for the come back,,
I'm getting ready to put my engine together, :thumbup:
My dad gave me this clicker and I'm not to sure of it's accuracy,
I have my old beam style wrench, I've been using for years, I trust it, but
I'd like to try the clicker, finally stepping up to the 70's, LOL :cool:

Bob
 
#7 ·
70, I know what you mean about wanting to check the accuracy of that thing before using it on your engine, I probably go a little overboard when I assemble an engine and have my wrench checked first if it has been used for any thing else in the recent past. Don't forget to "warm up" that clicker by first cycling it at the desired setting a few times when you get ready to use it. As far as the beam type if used properly they are very accurate and I myself even prefer them to a clicker but then that is just me. :)
 
#8 ·
A couple years back, Stock Car Racing Magazine had an article on how to check the calibration. If I can find the article, I'll see if I can type it out. I believe it used a "fixed, known weight" one gallon jug of water and a fulcrum to see the percentage it was off at a given torque setting. You just adjusted for the "off percentage" by adding that percentage to your old setting. If you follow me. I'll see if I can find it.


In a while, Chet.
 
#10 ·
Sbchev, Good point about leaving it on the setting for any length of time. There are a few no-no's such as NEVER pull on the wrench past the torque setting and never back it off much past the min. setting, loss of calibration can occur if you do either and of course as already mentioned never leave it on a setting.

NEVER, NEVER, NEVER let anyone use your torque wrench unless you are absolutely certain they know how to properly use it. Also NEVER EVER use a tool rental torque wrench because you have no idea how it has been treated and in all probably it has been abused to the max! :nono:
 
#12 ·
I have a one 1/2" MAC click-off style since the sixties and instructions then were to leave it rest @30ft lbs. I have a MATCO 1/4" that I have never used and can check the instructions.

Most tool trucks can send them out for calibration (and yes it is good to check on a scheduled basis). I think I have the name of a calibrater here...I will have to try and find it.

I understand the new models can be left at whatever setting, but all of this depends upon quality of the tool.
 
#14 ·
Weird, If you are talking about a 1/2" drive that probably won't hurt a thing and could very well be a good setting to leave it on. If it is a 1/4" drive then it is a bit on the high side for most but most likely no harm done here either. Probably the biggest destroyer of calibration is over torquing past the setting, that will get one in a hurry! I have even known guys who would grab their torque wrench, because of it's long handle, and use it for a breaker bar :rolleyes: without giving any thought at all to calibration loss, of course these are the guys who can never seem to figure why they have all the bad luck. :)
 
#16 ·
Do you mean you should return it to zero when your done?
Or the manufacturers reccomended setting. The way it works is (simplified) basically this: The setting sleeve is acting against a calibrated spring, which pushes against a deflection beam. At the end of said beam there is a ball, which fits into a detent in the ratchet head base (inside the torque wrenches "neck". The click you are hearing is that ball "snapping" out of it's detent. The sleeve is on fine threads, and the more you turn it to increase the setting, the more you compress the spring. Leaving it highly compressed for long periods of time will cause the spring to take a set, and no longer apply the correct force to the deflection beam, thus causing inaccurate torque. Backing off past the "0" setting can allow the spring to come out of it's pocket, and then be compressed unevenly, or more than you intend, thus causing inaccurate torque.

HTH

Garth
 
#17 ·
Not sure exactly how they work, but most clickers are spring style. You turn the handle and compress the spring. Leaving a spring in a compressed state tends to change its spring rate over time. This is why you either want to leave it unloaded (zero) or at 25 to 30 ft-lbf (value most manufacturers put in the instructions). Snap-on uses a different method on theirs. The adjustment doesn't load up a spring. I think it moves the fulcrum. You can leave them set wherever and it is not supposed to be detrimental. I still always drop mine down to the lowest setting out of habit.
 
#18 ·
i prefer to use this...

that 1/2 inch mac was off between 10 under (averaged 5 - 7 under across most settings) setting to 1 over (1 over @ 250 ft-lb) setting across the setting range of 50 to 250 ft-lb... not only do you have to be aware of accuracy but repeatability is a major factor... i therefore take a minimum of 3 clicks per setting and often 5, average and then do my graph so that i can interpolate my setting to achieve desired results.
 

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