I had to take the Forward-Facing Rowing System apart to make a change before I fit it to my Whitehall, and in the process of removing the 8 stainless-steel nuts and bolts, I found that seven of the nuts wouldn’t budge, and the only way to remove them was to twist until the bolts sheared. I may have twisted an odd bolt or two off in the past and chalked it up to corrosion, but to have seven out of eight new bolts go was odd. (In defense of the Forward-Facing Rowing System, the change I made was unique—the bolts don’t normally need to be removed.) I thought the ends of the bolts might have been damaged, but some of the bolts that sheared had several threads extending out of the nut and they looked like they were in good condition. I didn’t try a shot of WD-40—there wasn’t any sign of corrosion.
I took a look on the web and discovered the phenomenon is called “galling”—“thread galling” when it happens with nuts and bolts. Galling is also called “cold welding” and occurs when susceptible metals undergo a lot of pressure and friction. Nuts and bolts can literally be welded together. Galling can be prevented by giving the threads should get some lubrication before nuts and bolts are joined. I had a very old tube of anti-seize goo in my shop—I had’t used any in years—and to my surprise the label said “anti-galling.”
I bought a new set of bolts and nuts and gave them a smear of anti-galling goo before I installed them on the rig. In the future I’ll used the goo more regularly to save a few bucks on ruined fastenings.
After I’d bought the replacement nuts and bolts, I was on my way out of the hardware store with a handful of stainless steel just as another customer who was about to leave came up behind me. I waited a moment and held the door open for him. He went through without saying thank you or even putting a hand on the door. He passed by me less than a foot away but didn’t even look at me. Now that’s what I call galling.