I believe in doing the job right the first time and wanted to know what torque wrench do you guys use. I picked one up at Autozone that was relatively cheap. I got one good use out of it. What I used it for was for a high torque application which was for tightening down my head after I replaced the gasket.
I have noticed that much lower torque requirements on smaller bolts. This torque wrench is not reliable on these lower torqued bolts. What do you guys have for the lower torqued bolts. The price ranges for torque wrenches are all over the board. Thanks.

 

i use snap-on, but for the DIY person they are just too damn expensive. check out tooltopia.com. they have decent tools at decent prices. torque wrenches are a tool you don't want to cheap out on though.

 

To cover a reasonable range of torques, you need to get all three wrenches: 1/2", 3/8" and 1/4" drives (though the 1/4" drive is really for that fancy carbon bicycle; you won't have many fasteners on a truck that could benefit from that).

Me, I'm quite happy with the wrenches from our friends at Harbor Freight. Whether you go Snap-On, Mac, or HF, you do need to think about calibration, at least after a while. There are a number of You-Tube videos that claim you "can" calibrate a torque wrench by using a digital adaptor like this: http://www.harborfreight.com/12-in-d...ter-68283.html . Of course, that's no more than comparing the calibration of one wrench to another; is the other one correct? Maybe if you use the electronic one only for calibration. (If you go that route, you have to get all three drive sizes again to cover the complete range).

 

3/8" = 40 year old craftsman; 1/2"= snap on but I believe in buying made in usa whenever I can.

 

I purchased a new 1/2 drive SnapOn a long time ago. I decided to take a chance and purchased a used 3/8 drive SnapOn from epay and got lucky. Lastly I purchased a German made Syntace 1/4 drive wrench. It has both N-m and inch pounds on it. Scope is right, it came from a bicycle parts supplier and doesn't see much use.

I've read it a few times that torque wrenches are most accurate in their middle range, something to think about.

 

There is also an interesting video of a guy testing his wrench on YouTube. He was using weights at the end of the wrench. I'll see if I can find it.

The name doesn't matter as long as it is accurate. To that effect always turn it back down to 0 when done.

 

I got one of those you dial up and clicks. Except I found out it doesn't always click. I've broken a few bolts off and got some bad torque values from it.

Now I use an I-Beam torque wrench and calibrate it using weights. The only thing is it's sometimes hard to view the dial directly from the top when working in some spots. i thought the more expensive clicker style would have been better but the I-beam is allot cheaper and way more accurate.

 

I think I've seen that one; he's using weights from a bar-bell set. How accurate do you think those are? +/-20%?

It IS better than nothing. Too much vibration can loosen the calibration stop on my wrench and I can end up way off. If you're willing to put up with something that isn't NIST-traceable, I recommend using one of these: . Chuck up the wrench on something solid (a lug nut), measure 12" down the handle, and pull up with the scale until it clicks.

 

Many torque wrenches are longer than 12", especially the larger capacity 1/2 inch drive ones. The wrenches calibration takes this longer length into consideration. Weighting, or pulling from the 12 inch point won't give correct values.
Any wrench should be pulled from the center point on the hand hold when attempting to calibrate it, no matter how long, or short, the wrench is.

Edit: measurement of effective length must then be made and math must then be done to reduce the values found to foot pounds at the center.
I have watched torque tools being calibrated in aircraft engine shops.
They used snap-on calibration machines that did not require all this rigmarole.
It's not so easy to do a precision job at home.

 

Torque is torque, no matter where it is applied. I agree that if you are going to put 150 ft-lbs on a 150 ft-lb wrench, it is strongest when pulled from the hand-grip. But 75 lbs at the 12" mark is exactly the same torque as 64.28 lbs at the 14" mark. If you want to do all the math each time, you're welcome to it. (Of course, my 1/4" drive torque wrench isn't 12" long. But then it's calibrated in newton-meters anyway, so math is still required.)

Calibration machines seem much easier because they don't worry about the length of the wrench; they are applying pure torque to the head. You just drop the wrench in and push the button. Replicating this at home does require a basic knowledge of mechanics (torque) and a tiny bit of fabrication.

In the end, the problem with any calibration is "tracing" your calibration back to something you're sure is accurate. You can compare one wrench to another just by hooking them together with the appropriate size socket, but it's only a comparison. If your shop-built calibrator uses buckets of water (actually a good way to get a repeatable weight), then it's only as accurate as the volume measurement of the water.

But any calibration is better than just pulling a used wrench off eBay, so go at it!

 

All true, but high torque applied on long wrenches causes some small bending of the whole wrench mechanism. This deformation ( more properly, lack of it when pulled at alternate length) can cause the click-stop device to click at inappropriate force levels. If any precision measurement is expected from click-stop type wrenches, they must be pulled from their design point. Same is absolutely true of beam type wrenches.

 

Even though the guy in the video I mentioned was low buck the way he explains the method seemed solid and he used the length of the wrench to find exactly where to place the weights. Yes if going to use weights for verification then those weights must be highly accurate and barbell weights aren't known for their accuracy. I have seen the weights they use to calibrate scales and they sure aren't using China made barbell weights.

The video was mentioned as an example, again common sense must be used.

 

Before y'all get too wrapped around the axle getting the last 1% of accuracy out of your torque wrench, keep in mind that the actual object of bolt tightening is to put a given axial load on the bolt. At best the relationship of bolt torque to axial load is probably about +/- 30%, depending on thread and surface cleanliness, lubrication, and other second order effects, so even with a perfect torque wrench the final results aren't all that precise. That's why critical bolts such as head bolts are usually tightened by "angle torquing" these days instead, which isn't really torquing at all, but translating precise angular rotation into bolt strain and consequent axial load based on the thread pitch.

The small 1/4 inch drive torque wrenches are good for measuring bearing preload. A beam type is best for this application.

 

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