FWIW, I replaced the "new" bolt with a virgin new one yesterday.

I couldn't help but wonder: how much damage was done by accidentally unscrewing it instead of tightening.

WTH? you are probably thinking what's he talking about. In process of tightening nut, I put my impact wrench down on its side. Picked it up and continued torqueing it down - pulled trigger and watched nut spin wrong way! Putting impact wrench down on that side pushes direction button from forward to reverse...

After putting new nut on I looked at it and wondered:

1) how does any one measure above 200 ft pounds?

2) what would happen if I used the nut I just removed as a lock nut? So I picked it up and finger threaded it on the exposed axle grooves. Nothing, it just spins, no connection. Interesting I started to wonder, so I flipped the nut over and finger threaded it on from other side of nut - sure enough it caught.

I removed the nut and observed. The inside threads are now tapered !! The act of torquing it down actually distorted the inside threads at one end of the used nut to the point it can't grip.

yes for a minute or two I wondered if the axle shaft it if the darn nuts were made with a taper. If the later it was 50 50 chance I put the newest one on right.

then I realized this is why these are use once nuts. Thought you might be interested.

maybe should have started another thread but: how do you measure torque settings so high as this bolt gets? Recall is that it is above 200 ft lbs. About all I can do is sit an impact wrench on it and torque until no movement shows.

John

John

 

it is easy. simply have a torque wrench rated that high; they exist. you can also use an impact wrench rated at this value if your air pressure conforms to its rating; most overlook this. there are adapter extensions for impact wrenches known as torque sticks that limit the torque to a range. finally, mechanics develop a feel for fasteners. even with lug nuts i can place my foot on the ratchet wrench and feel that the torque is correct. it is hard to describe, but when tightening bolts you feel the change in resistance when the tensile force is correct. try a long breaker bar and you will feel when the nut is tight, just before it wants to stop.

 

Thanks Cor!!

John