Tormania

I bought a Craftsman Torque Wrench and used it for the first time this last weekend. The wrench is the type were you turn the handle to set the torque setting, from 25-250lbs.

I was putting a rear wheel back on and was getting ready to torque the lug nuts on with an increasing 30-60-100 lbs star pattern, to ensure even tightening of course. At first I wasn't sure how to tell when I reached the torque setting with the wrench and had to re-read the instructions to figure it out. (I've never used a torque wrench of any kind before so this is all new to me) I assume that I was correct in tightening nice and slow until the handle on the torque wrench gives just a bit. After I had done this for all 5 lugs at 30lbs I adjusted the wrench to 60lbs and started again. I was VERY surprised to notice that when I went to tighten the lugs from 30lbs to 60lbs that the wrench turned hardly a 1/8 of a turn before the handle gave and notified me that the torque setting had been reached. :confused: :confused: I thought for sure that going from 30lbs to 60lbs would warrant at LEAST a full revolution of the lug. The same thing happened when I went from 60lbs to 100lbs, the wrench again didn't even complete a ¼ revolution before it released.

I'm hoping that other owners of this wrench can put my mind at each and confirm that I did indeed use the wrench properly and that my wheel is on with the lugs tightened to 100ft-lbs of torque. I have since driven on it and it seems fine but I'm still uncertain that the proper torque settings were done. I'm used to tightening nuts until you can't turn them any tighter and I know that is incorrect for lug nuts, but the difference between 30ft-lbs and 100ft-lbs should be more then ½ a turn, shouldn't it??? :confused: :confused:

Don Baldwin

I have the same wrench. After setting the torque by adjusting the handle, once you reach the set torque you will hear/feel a click. At that time you have the correct torque as set on the wrench. The travel once you reach 30 Lb/Ft to 60 or 100 really will not be that much travel. Set 100, hear/feel the click, you are OK.

Patman36

I have a Craftsman torque wrench... it works good and is like you described (turn the end of the handle to get the right setting). I like it :)

Patrick :jester

Lil Red

You have done everything correctly! This is the deal. Once a bolt, lug nut or what ever makes contact with the surface (in this case your wheel), the torque builds very quickly. Sometimes the difference between breaking a lug off or the lug nut being properly torques is only a matter of .75 - 1.5 of a turn. My point is that, as you have seen, it is very easy to overtighten a lug nut because the torque multiplies very quickly once the nut starts to make contact with the tightened surface. Hopefully this helps!

pewterhdtop

The wrench you describe is one of the better choices, it will audibly click when the setting is reached. A couple of items of interest, torque wrenches are not very accurate at the lower 10% of their scale (we do not allow their use in the bottom 10% of range in Aerospace), you need to be carefull if you are attempting to torque something by turning the wrench to the left (via configurations with a crows foot) because most will not click in this direction, and if you use the wrench with an extension you can alter the true torque at the fastener (with basic trig you can adjust for this).

It is not unusual for the fastener to only move a little bit (less than 1/4 turn) from one torque setting to another. Once the fastener is tight, you are only adding additional pre-load to it.

Hope this helps. :cheers:

RWhite

Make sure when you are through with the wrench, you "relax" it back to the minimum setting.

It is a nice wrench. Sears had it on sale one day and after looking at the other Torque wrenches for sale at other tool stores, this one is by far the best.

ruking1

Another thing with torque wrenches is:always torque with a pull stroke not a push stroke.

Tormania

Thanks for the replies guys! I finally didn something right! WHEW! :lol: :lol:

alanh

ruking1, thinking about your statement, I really would like to hear an explanation of the difference of "pull stroke torque" vs "push stroke torque". Thinking about how I put lug nuts on, I always have pushed down on the wrench with my right hand/arm to tighten lug nuts. :confused: :confused:

MikeV

Correction for Pewter hdtop. An extension will not change the torque, a crows foot will. I have verified that this is true on our torque analyzer.

Thanks, Mike

jschindler

Interesting, I have always heard the extension will make a difference. In fact, I thought some torque wrenches come with a warning about that. I can't confirm, just sharing what I had heard in the past.

I have the same wrench and agree with what has been said above.

ruking1

First of all it gives a clean, consistent, more controllable pull force, i.e., the force tends not to be jerky like a push stroke can be. I actually learned and practiced this distinction in nuclear weapons operations where believe it or, almost ALL if not ALL fasteners have a specified torque value.

hog

Trust is a must...

Sixguns

While all the info you guys gave is great, the most important part of obtaining proper torque is to acheive torque while the fastner is in motion. if you stop rotation during a pass and then "click" upon the start of rotation you just got a false reading . in that case its best to loosen the fastner and retorque if you want it done right.

HOCKEY

What does this cost at Sears? Thanks.

Lambinator

....static friction vs. dynamic friction.

And to add to what was already said - extensions do NOT affect the torque - torque is simply the amount of force required "X" distance from the center of rotation. So adding a 1" extension or a 12" extension along the axis of rotation would not affect the torque reading.

CJ-Z06

Mike you are right and there is an equation that is used to compensate for the crows foot.

E - Effective length of extension (crows foot) measured along the centerline of the torque wrench

L - Lever length of the wrench,,, center of grip to center of drive

T(W) - Torque set on wrench

T(E) - Torque applied by extension (crows foot) to the fastener.

T(W) = T(E) L/L+E T(E) = T(W) L+E/L

BTW this is all in the manual that came with your torque wrench, I have the 3 size set of Craftsman Torque wrenches they are nice. One more thing,, they are for torque setting, not loosening and general use. They are not considered a general use hand tool and they are not covered under the normal Lifetime Warranty that Craftsman carries, because of the classification they give it.

pewterhdtop

My thought process on an extension was one that increases the distance of the socket from the center of the point where torque is measured in the wrench. As some have pointed out, a regular socket extension will not cause a defference in torque reading, however, an extension from the center of torque may cause a difference in the measured verses actual value. Included in the equation is the effect of the angle, since the Sin (or Cos it has been a long time since anyone has used any angle in my business) varies with the angle. I have a handy dandy guide somewhere around, when I find it, if anyone is really interested, I will forward the info to those that ask.

The equation listed does a good job of compensation. In the case of a crows foot, unless you have your wrench calibrated, the uncertainty due to the difference in applied verses intended torque is minimal unless, of course, the effective length of the crows foot or other "extension" (from the centroid of measurement) is greater than the normal 1 inch or so. In my business, it may be required to use a six inch extension at an angle of 45 degrees, in cases such as this, the measured verses actual torque can differ substantially!

Sorry for any confusion! :cheers:

Tormania

Well after all this discussion I got home last night and not only had I lost a lug nut cover, but that lug had backed all the way out and I was surprised it was still on the wheel!!!! :eek: :eek: :eek: I don't know what the hell happened but I torqued that lug back up to 100lbs and I had a spare lug nut cover to put on it. How could a lug come untightened when I was 100% sure that I had tightened them all properly to 100lbs?? The other 4 were just fine. :confused: :confused: :mad

Mark S.

Tormania...I don't know what happened...but the good old fashioned way of just tightening with your good 'ole trusty lug wrench it until "you know" that it's tightened will work just as well. Heck, do you think that when you have your Vette serviced that the tech will use a torque wrench...bet he doesn't. :yesnod:


[Modified by Mark S., 10:10 AM 5/22/2002]


[Modified by Mark S., 10:10 AM 5/22/2002]