Now you went and got my brain zooming in on what just might make pens operate more smoothly. Seems we'd only want to use a product that won't contaminate the products that the pens are designed to dispense. WD40 is primarily a penetrant that at 1st is not a particularly good lubricant, but gets better with time as the solvent evaporates but that evaporation continues until the WD becomes a thick waxy like substance that is a great protectant but not a great grease. I'm thinkin a small amount of a gun lubricant CLP (cleans,lubricates,protects) would serve as a more semi-permanent solution. Problems could arise because the spiral shaft of the pens I have examined are all some unknown plastic that could be attacked by the solvent carriers of what ever lube is used. The primary lubricant that is used in the CLP's I'm familiar with is Teflon and, as is WD, they are approved for use on food processing equipment. The spray on application of WD would coat all of the internals of a pen whereas CLP could be sparingly applied with a foam Q-Tip and would stay where applied. I have 2 V2s ,that I don't like, that I will try this out on. Depending on the results of that experiment, I have a V1 ,that is my current go-to pen, that I will consider for the same treatment I also have a new Savio that I have only used with water for trials of accuracy and smoothness after a couple dozen runs for break-in purposes that I like a lot which may be a candidate for this test. StandBy for reports to this thread...
Spent my working career as a research and development mechanic for a large aircraft manufacturer. Got to work with many highly skill mechanics and some incredibly smart engineers. If they could think it up and draw it, we got to build it. After all manner of extended torture tests, we got to test till destruction. Example is we bolted a test aircraft to the floor and lifted the wing tips till the wings broke. 16 feet and the boom of a shot gun blast then we got to tear it all down and sent the fuselage out to the bone yard.