Graphite oil is an interesting lubricant worth special mention. The most commonly available form available in small quantity is lock lubricant, available at a local hardware store or building center, or possible from any auto parts store. Picture here shows a common brand "Lock Ease". It is a light mineral oil containing high concentration of powdered graphite. The graphite powder will settle out of solution, so shake well before using.

My most common use for this lubricant is exactly as named, to lubricate door locks. It works very well for freeing up sticky tumblers or pins in key lock tumblers. Squirt a little into the key slot or apply some onto the key before insertion. Wiggle the key a bit and operate the key to turn the drum back and forth multiple times to distribute the oil inside the lock mechanism. Like magic the key lock will (usually) free up and work as new. This oil can also be used on other parts of lock mechanisms.

The idea here is to use the light oil as a delivery vehicle to get the powdered graphite into the mechanism where it is needed. The light oil also serves as a penetrant and temporary lubricant to help free up sticky mechanisms. When left in place for extended time the oil will eventually dry out leaving the graphite material in place to serve as a long term dry film lubricant. This works well for parts that are exposed the weather outdoors, ergo door entry locks and door latch mechanisms.

There are other nifty uses for graphite oil. In general, in may be used in many places where unattended long term lubrication is needed, and in particular when the oil is expected to eventually dry out. It is not good for heavy load bushings such as automotive suspension parts. It is good for light load applications where dry film lubricants may be appropriate.

One of my favorite "odd" applications for this oil is in the felt sleeve bushings in my MGA steering column. The factory may have used no lubricant here. Most people will use engine oil here. It may stay put fairly well in the felt bushing, but will eventually dry out. That can leave a sticky tar like goop that may ultimately cause friction drag and fail as a lubricant, actually promoting future wear on the felt material. I used graphite oil here with new felt bushings in 1986, followed by total neglect. After about 100,000 miles in 10 years the top felt bushing was loose enough to find a little radial free play (if looking for it) but not enough that most people would notice while driving. Several years later around 185,000 miles the accumulated free play bugged me enough to replace the bushings again I completely soaked the felt material with graphite oil. Today (11/19/2010) after another 6 years and 50,000 miles there is no perceptible radial play in the upper steering column other than the normal slightly soft feel of the felt material (if I push it hard enough). I will give the felt bushings an "A" for endurance of a simple and cheap part, given the good long term lubricant.