Beam style torque wrench

[Anonymous Poster]

I've used this torque wrench for a long time but I have never checked it for accuracy. I will call some of the local auto parts stores to see if they have a calibration unit (there is an Auto Zone not far from me). I also have a neighbor whose son is a Service Manager for a very large automobile dealer. They may have a calibration unit at their shop.

I don't think there is much that could go wrong with a wrench of this type. It's never been dropped or abused in any way. I just wondered if the flex characteristics of the beam would change over the years, causing it to be inaccurate.

John

 

[agcomike]

the clicker style has a lot of parts and springs probaly not exactly sure but i've been told by mac and snap-on that the click style is less accurate because of parts but it is easier to use.. the beam type has only 1 part and isn't hardly effected by abuse..

Not exactly sure but my craftsmen digi-torq still seems accurate.. but who knows they recommend it recalibrated every year or after impact..

 

[Trev]

Could these torque testing devices tell me approx how much torque I'm applying with my air impact wrench in each of its four settings, given a certain PSI of air pressure driving it? Sounds like this might be a good way to get a feel for what the wrench is really doing?

 

[MDNick]

JWE,

Yep. Assuming the torque wrench reads out in ft lbs. If not, then, well, no. /forums/images/graemlins/grin.gif

As to any changes in flex characteristics, I wouldn't think so. Only way that happens is if it is left loaded for an extended period of time, common in 'clicker' types, but not possible for beam types. Or if it has been flexed repeatedly, constantly, to the point of metal fatigue. I assume you are not that rigorous with your torque wrench use. The beam types should remain within their calibration tolerance pretty much forever. The 'clicker' types also stay in cal relatively well if properly cared for, ie, don't drop it, or store it loaded.

Nick

 

[Bird]

Bob, there are instruments specifically for measuring the torque output of air impact wrenches. Of course, they cost over a thousand dollars. I think if you're concerned about torquing to a specified amount with your impact wrench, your best bet is a set of "torque sticks." You can get them various places, so Matco Tools is just one that you can look at and read about.

 

[Trev]

</font><font color="blue" class="small">( Bob, there are instruments specifically for measuring the torque output of air impact wrenches. Of course, they cost over a thousand dollars. I think if you're concerned about torquing to a specified amount with your impact wrench, your best bet is a set of "torque sticks." You can get them various places, so Matco Tools is just one that you can look at and read about. )</font>

Thanks Bird! A guy at a car shop told me about those too, but when I asked he said they cost a fortune. Doesn't look like that at the site you sent me. $45/stick, and I really only need one.. for changing the car tires/wheels twice a year and occassionally hitting them to make sure they're tight. Everything else a torque wrench is fine for, but I sure get tired of not being able to use the air wrench on the cars.

Thanks again,
Bob

 

[Anonymous Poster]

Trev,
I use my air gun on lug nuts, I just set it a bit light then when I set the tire back down I torque it to specs with a torque wrench. Still saves time and arms /forums/images/graemlins/smile.gif

 

[uhmgawa]

</font><font color="blue" class="small">( </font><font color="blueclass=small">( What I have done before was put a bolt and nut through a hole in the center of a flat bar, and hang a known weight off the flat bar a measured distance from the central bolt. The bolt which you 'torque' acts as a fulcrum, the torque wrench handle is secured/held however easiest, and you simply read the weight on the pointer scale.)</font>

uhmgawa... does this mean that if I hang 40 pounds, one foot from the center of the bolt it should point to 40 on the torque wrench scale? )</font>

Yes. You might want to use longer distances from the center
in order to increase the accuracy of the load. So 40lbs at
1 foot would load equal to 20lbs at 2 feet.

On the subject of accuracy of torque wrench clicker-types vs.
deflecting beam versions, both rely on spring tension to
sense the load. However the deflecting beam is an elemental
spring where the clicker-type has a mechanism in addition to
a load spring and will have more error variation over time
due to frictional losses and mechanical wear. The
deflecting beam is about as simple as it gets.

 

[Anonymous Poster]

I agree with Hinomoto mike. The beam style may not be as accurite as a ratchet/click type but it is far less apt to get out of calibration. The ratchet type depends on a coil spring maintaining its tension for calibration and when put away with out backing the setting off all the way it will change tension very easily. the beam type depends on the big bar maintaining its tension and it is never put away under tension. If the pointer does not read near zero you might want to bend it or, take it into consideration when reading it.

 

[Anonymous Poster]

Mike... I checked all of the auto parts stores in my area and none of them have torque wrench calibration units. I think my best chance is to talk with my neighbors son who is a Service Manager for a very large car dealership. I will probably see him over the weekend.