[mikewarot]

It wasn't intended to be a lubricant. When it "dries" it gets gummy. Quoting Wikipedia[1]

  The spray, composed of various hydrocarbons, was originally designed to be used by Convair to protect the outer skin of the Atlas missile from rust and corrosion.[11][12] This outer skin also functioned as the outer wall of the missile's delicate balloon tanks. 

[1] https://en.wikipedia.org/wiki/WD-40

[hansonkd]

From the article:

> It acts as a lubricant, rust preventive, penetrant and moisture displacer.

and the article is in the category of "Petroleum based lubricants"

So it seems just because it wasn't intended as a lubricant doesn't mean it can't be be.

[sliken]

Sure, but if you don't know what you are doing, and have a need for lubricating something at home, on a bike, or on a car, you are MUCH better off with a oil, graphite, teflon, or grease.

Sure professionals use WD40 when appropriate. Sure WD40 lubricates great, for seconds to minutes (before the volatilies evaporate off, thus the WD40 smell), less well after that (somewhat gummy residue) and might well stop a creak. But won't lubricate nearly as well as oil or grease or last as long.

[SAI_Peregrinus]

It lubricates for a very short time, then most of it evaporates & leaves behind a slightly sticky residue that helps prevent rust. It dissolves most lubricants that would stay in place for longer (greases) and cleans them off of surfaces.

[dharmab]

Wikipedia says a lot of things. Many of them are wrong.

Ask anyone who works professionally with machines and they'll tell you WD-40 is a temporary lubricant at best.

[stcredzero]

Surely, there is some context where WD-40 is just fine.

I do note that lubrication is actually complex. Soap feels plenty slick in general, but if I try to shave with it, certain soaps give very poor results. So, of course, not everything slick and oily is going to work for lubricating machines.

But when I rub soap on wood screws, it works just fine in that context!