If you clean off metal with WD40 and leave it, it goes rusty. It does not if you use oil. Just because it disburses water does not mean in is is not slight hydroscopic. Diesel does the same thing. It is not the correct product for this job, nor for the switch, really. Its seductively useful in its self propelling tin.mat_fenwick wrote:WD40 Hygroscopic? That's a bit of an urban myth - I've yet to see any evidence supporting it. What it does is displace moisture, not absorb it!
Also, PTFE in itself is not hygroscopic. However, you may get items which are described as PFTE but are in fact made from another material (e.g. nylon, which is hygroscopic) with a percentage of PTFE added to help lubrication.
Anyway, this is getting away from the OP's question which was to do with the lighting stalk!
Would need to check on PTFE/Teflon. An engineer told me about this. It is pertinent to Messerschcmitt steering and king pin bushings. The answer is the correct grade of stainless steel. Mybe the oil is a different technology to the solid version you can machine.