Willie,

"If it ain't broke..." I guess I wanted to point out that although it has good uses, almost anything is better than WD-40 *for lubrication*. Also that IME, the Leathermans can be a bit of a PITN lube-wise.

Galling is, hmmm, well, sometimes when two metal surfaces that touch each other move, surface metal on one surface sticks to the metal on the other surface (and tears off the parent part). The mating surfaces get "rougher"; resistance to movement gets higher. Here's an example of galling that you may not be able to see naked eye but can easily demonstrate to yourself; it came to my notice when scouts were builfing pop-can alcohol stoves: Use an aluminum "nut" like a pop-rivet threaded fastener and an aluminum screw to match. At first, they run in and out fairly freely. Now use alcohol on them. After as few as one application of alcohol - greatly exacerbated by heat - the screw "siezes up" in the nut. If we use, say, a steel nut and an aluminum screw or vice-versa, there is no problem - no galling.

Galling is frequently a problem with same-alloy surfaces and sometimes a problem with dissimilar alloys. Think of it as microscopic welding together of the moving surfaces - because that's basically what it is. Increase heat or pressure or both and galling problems usually go up orders of magnitude.

So IME, a tightly assembled Leatherman tends to have very noticable galling problems. The only practical way to prevent the problem is to prevent the surfaces from touching - moly disulphide treatment or PTFE does the trick if you can get the particles into the contact area. On a very tight joint, finely divided moly may be the only possible cure, but remember my caution about possible corrosion under a moly plating. Some oils will also work, depending on contact clearances and assembly clamping force as well as the specific properties of the oil.

This propensity to gall is a known physical characteristic of many alloys and tends to be typical of many (most?) of the non-rusting steels and is rarely a problem with plain carbon steel alloys that are properly hardened. Some non-rusting steels *are* very resistent to galling, of course.

Bottom line? Use what works. But a stiff Leatherman is only going to be helped momentarily with WD-40, if that.

HTH,

Tom