...you can still hammer on them an go well beyond its limits and unless you check it with a torque wrench (defeating its use) you don't know if its accurate. You cant send fatigued steel off for calibration.
So even by the forgiving torque standards of automotive work, a torque stick is not something I personalty trust.
Actually, this is EASY to test. Just draw a line straight down the length of the torque stick. If it is fatigued, the line will show the permanent twisting. If the line remains straight (when not under stress), that is proof positive that the stick has never fatigued.
Still, I wouldn't advocate using a torque stick here, or for torque critical uses, but I do like my torque sticks in the case where I want to run the torque up with the impact but finish with a torque wrench. I'll just select a stick that's a step or two below the final torque.
If you do this, the line test above is unnecessary. This is because once a torque stick has begun to permanently twist (as it exceeds its elastic limit and starts to plastically deform), I would expect it to eventually twist off due to fatigue, and we have heard absolutely no stories about torque sticks snapping, so I would guess that this is just something that does not happen (no surprise here, as they're engineered for the job). And more importantly, once the torque stick starts to fatigue, it will deliver LESS torque to the fastener. So if followed up by a torque wrench as I advocate, a torque stick cannot cause any harm.
So all this talk about torque sticks being evil is just by people who do not understand how they work.
