Thanks You all.

Bowtech suggests lubricating only the pivots with any oil but WD 40 period.

I don't want any lubricant that could let a greasy mess in the bearings.

graphites seems nice : I have a forrester kit
graphite kit
for coating collets before reloading. I think I go and try it.

I have no idea of what railroadmen use on the tracks. As in France railroads are almost the property of the declining but potent communist party, no chance that I go and begg them anything. Moreover if it's a messy business, my wife that hardly put up with my hunting crazes, will kick me out. Imagine a guy my age, 55, forced to roam nightclubs and bars to find a new damzel??????? let alone dealing with nappies and such. Bigger is best, You sure you could be called a friend ?

Let's try mica motor. Then I am going to ask Bowtech.