Lubricant is not the major component in WD40.
The WD stands for Water Dispersant. Yes, they tried 40 different formulations before they hit on the perfect one to disperse water on certain components of Minute Man missles. Originally, WD40 was actually classified. But, it worked so well for so many different things 'round the old silo that eventually the missle repair men started using it all over base, and finally taking it home. So, the spooks gave up on keeping it secret. It's actually part of your peace dividend. So, don't ever say that nothing good came out of the Cold War or that defense spending is all wasted.
Anyway, WD40's lubrication ingredients don't work very well until all of rest of the components (which are quite volatile) evaporate.
Personally, I think WD40 is one of the most versatile things you can have around. If you've got a can of WD40, a roll of duct tape, and a good knife, you're ready for most anything. Throw in a Leatherman PST and you're invincible.
For example, WD40 is FDA approved for use in food service. I've got a lot of recipes that begin "grease the pan." I'm no professional cheif and I guess I don't have very good equipment. None of my pans, not one, has a grease port fitting. I've got my grease gun right here, but there's no place to hook her up. Besides, none of my pans have any moving parts. So, I've found that a quick spary of WD40 before use keeps 'em working fine.
As for the knife that's a bit tight after a hot water wash, I'd suspect expansion of the materials. Try gently heating the knife with a hair dryer and see if this produces the same result.
On second thought, while the gentle heat idea is nice, another test would be to throughly rinse with cold water after you get the knife clean. If it is thermal expansion, this should set everything right again.
After water wash, it's important to dry the knife out. I prefer compressed air. Then, it is important to get a bit of lubrication in there. I like a product called Tetragun oil. It's a Teflon based lubricant sold as a gun oil at better gun shops. It's pricey, but they have a little bottle available and you only need a couple of drops to lube a knife. Since it's Teflon based, it actually consists of solid PFTE bits suspended in a carrier. So, shake well before using. Then, after applying it, you have to work the knife back and forth many times to grind the little PFTE bits into the metal surface before it'll really get nice.
Chuck
[This message has been edited by Gollnick (edited 20 April 1999).]