rat907 wrote on 02/22/13 at 06:44:26:


I will accept that if the rotational axis of the beam wrench is not aligned with the center of the object being torqued, the values might vary some,.. but only because there might be some additional friction in the joints as they act somewhat like a crude u-joint.  But,... torque is torque.  

If what you are implying were true, then if you got ten extensions, snapped them all together, the torque at one end would be way different that at the other.  That would not happen.

When I was a mechanic in the Army, we had to use crow's feet on the torque wrench, and there was a formula (which I no longer remember) to correct torque values.  As far as which is more accurate, a properly maintained and calibrated clicker is.  As far as which is better for a shade tree mechanic, definitely the beam.

cant be much....

You can calibrate a torque wrench pretty easily if you just want to make sure it is in the ballpark.  The following is not real precise.  There are shops that do this for real and will charge maybe $50 to calibrate and adjust a torque wrench.  Just put the drive side in a vise (with some soft metal sheet to keep from putting vise marks on your wrench) and make sure the handle is level.  Tie a cord or safety wire 12" (that's one foot, bill) from the center of the drive.
  -- for a clicker, set it on a weight in the midrange of the scale,.. say 40 pounds.
  -- attach 40 pounds of something (I use lead ingots stored for bullet casting) to the safety wire and see if it clicks. Barbell weights are handy for this if you are confident in the weight being accurate.  Go up or down a pound or two or three to see where the actual click point is.
  -- for a beam wrench it is easier.  Just attach the safety wire at the 12" point, and attach a known weight to the wire. If the scale reads the weight properly, you're golden.  If not, you'll have to start carrying a correction every time you use that wrench.

A lot of our fasteners use inch-pounds.  So, if you want to test your smaller wrench graduated in inch-pounds, find two one-gallon plastic milk jugs (they weigh only a couple ounces each), fill them with exactly one gallon of water each, tie them together and you'll have a weight that is really close to 17 pounds.  Put the drive end of the wrench in the vise, set it on 102 inch pounds, and tie the two jugs on the wrench at a point 6" from the center of the piece clamped in the vise.  If it just clicks,.. marvy.  

Super Thumper wrote on 02/23/13 at 08:49:29:


I doubt it.  Clickers wear out.  The only thing that can happen to a beam torque wrench is to damage it.

If you took your cheapo clickers to a shop that calibrates these things, you might be unpleasantly surprised.

Have you tested them at all to see when they actually do click?

I like clickers because of the convenience, but if I am using one on a project where torque is really important (cylinder heads, for example) I always verify they are at least in the ball park by using one of the tests I mentioned above.  I don't have those concerns with a beam wrench.