Torque Wrench Accuracy- How to easily test (Page 2/2)
cvxjet OCT 15, 08:09 PM
I get that but here is the interesting "Contradiction" of the way they SHOULD be out of spec; When I used the short TW and my friend had trouble holding the engine, the head gaskets failed within 6 months (Admittedly from my experimental Mufflers), while when I did it with the 4 foot long TW, the head gaskets are still working great- no leaks of any sort; I torqued them back in 2004....so that is 14 years trouble free- and I take my boat out to the Delta at least 20 times for ski rides and such every year, and then also up to Trinity lake for 2 weeks every summer....60-80 hours every year.

You'd think the "easy one" would have been the time the gaskets failed......
PK OCT 16, 11:01 AM
Neat vid.

A vitally important part of using a torque wrench; often overlooked, is to exercise the torque wrench prior to use. Not a walk in the park but set it at 60% ish of the scale and pull 3 or more times. There is very often a significant difference atwix those initial readings and the proceeding pulls. If you are feeling particularly diligent you could repeat this excercise when set to the reqd torque setting. Especially important to the DIY user where the torque wrench may not have seen any action for weeks/months.

As to winding them off after use. It was drummed in to many apprentice heads over many years. It depends greatly on the design and components used.

For a shim tensioned torque wrench, backing off too far can remove all tension from the shims and allow them to rotate in the stack or collect detritus which can in turn alter tension. Particularly important for larger "clutch" style torque wrenches such as the norbar 5r.

Click and cam style that are spring/rod operated can normally be wound fully off.... But there are sometimes plastic drive/handle lock gears that have a hex inner section, if the torque wrench is over enthusiastically wound off every time, they can stick closed and the extra ooomph to release every time will eventually round off this hex section.

Norbar now do not advise to fully wind off their wrenches.

Cheers
PK (it's my job) :0)
theogre OCT 16, 01:26 PM

quote
Originally posted by olejoedad:
Always reset the torque wrench to zero after use to extend the calibration life of the tool.

Yes, Zero.
But never loosen more that many do allow.
Loosen < Zero can allow the "click block" to move inside many torque wrenches making to read way off or not working.

I've seen expensive wrenches need pro fixing and recal because of this. Many are used where they need certs to show tool reads correct w/in ±X%.

I return to Zero after use every time because don't use them much now.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Patrick OCT 16, 03:26 PM

Okay, I guess I've learned something about torque wrenches that I didn't previously know. I'll be diligent from now on about not adjusting my torque wrench below it's lowest setting when I've finished using it. Thanks to all who chimed in on that matter.
theogre OCT 16, 09:18 PM

quote
Originally posted by Patrick:
Okay, I guess I've learned something about torque wrenches that I didn't previously know. I'll be diligent from now on about not adjusting my torque wrench below it's lowest setting when I've finished using it. Thanks to all who chimed in on that matter.

While Some TW may like being fully unwound but unless your have doc's to prove that better to assume to set to Zero or lowest marked setting. (Some don't have a true Zero. Most are high range units for 200 or a lot more ft-lb not sold at most retailers. Often can hurt you just falling on your foot etc.)

Basically most "Click" TW are same idea.
In Short, Normally... Head will move a little on the pivot as "click block" (a block, cam or whatever) tries to rolls when spring and "hammer" can't keep them straight under pressure.
"Hammer" is just a name for part(s) between spring and "block."
Problem is "Click Block" is a loose part in a lot of them and w/o enough pressure the block can get out of position or worse. Depending on exact tool, Can do that w/o other issues or like vibration when stored can shake it out of correct spot.

Many expensive units still hate being set < Zero so you really can Save by setting to Zero.

I have cheap HF because is good enough for how much I need them. Still have a old Torque Limiting Screwdriver for computer work still cost $250+ for range of 0 to 100 in-oz. (under Utica brand and rerated 20-100in-oz.) That will click and spin all day when you reach torque. Sim to power drill/drivers w/ limit clutches.
Patrick OCT 17, 04:00 AM

quote
Originally posted by theogre:

Many expensive units still hate being set < Zero so you really can Save by setting to Zero.



Careful, you'll blow your long time reputation of being The Ogre.