I finally figured out why my torque wrench kept slipping

Been using a click-type torque wrench for 5 years and just learned last month I was supposed to grease the threads on the bolt, not just crank it dry, after a guy at the NAPA counter in Des Moines watched me struggle and asked if I ever heard of friction.

3 comments

3 Comments

the_gavin2mo ago

My buddy at the shop in Omaha told me the same thing after he watched me snap a bolt on a control arm. He said the torque spec on the box is for a clean, greased thread, not the dry friction you get from rust or dirt. I read somewhere that dry threads can add up to 30% more friction, so you're way over-torquing without even knowing it. Some guys swear by anti-seize instead of grease, but the principle is the same - you need that lube to get the right clamping force. Now I keep a little cup of moly grease right next to my torque wrench and it's made a world of difference.

skyler_white952mo ago

Gavin's dead on about the friction thing. I started using a little dab of anti-seize on my lug nuts after stripping one in a parking lot, and it hasn't slipped since. That little cup trick is smart, I just keep a squeeze bottle in my toolbox now.

abby_palmer1mo ago

Wait, have you guys seen that video from the old Snap-On guy who talks about how clean threads actually create more friction than slightly oiled ones? I read a forum post where a guy tested it with a torque wrench and found dry bolts could be off by almost 30 foot-pounds without even knowing it. That whole "dry is more accurate" thing is totally backwards. The anti-seize trick is solid, but I've heard you gotta be careful with how much you use because too much lube can actually make the bolt under-torqued, which is almost worse than over-torquing. I switched to a small brush-on bottle of anti-seize after reading that, just a thin coat on the threads and it fixed a lot of my gripes with seized hardware. Do you guys find that a little dab works better than a full coat though?