It's many years ago I've used a Campagnolo square taper on a road bike. Let's face another fact - they are engineered for a rather clean environment with major influence from the warm and sunny south Europe. The hubs, pedals, BBs and headsets BITD were awful with absolutely no kind of weather proofing at all. Is it any surprise that they went out of the MTB market?
Now I'm not saying they don't know what they are doing, but putting a small amount of lube on the Campagnolo cranks I had BITD did not cause any problems. Even with the very naff 7mm allen bolt they used for there self extracting bolts (as apposed to the Shimano 8mm bog standard bolt).
I have just checked some NOS Shimano UN72 I have, and guess what...there is an hotchpotch dab of white grease like stuff on the tapers......I assume there is a reason for that....or.....?????
I actually strongly disagree the square taper "clearance interface" is crap. This thread demonstrates (someone mentioned finding a bike that had been in a pond!) it can work and be reliable even without following basic engineering practices and with no maintenance at all. I would like to see some of these more modern interfaces that could handle similar situations over the long-term just for the sake of discussion; so far I've used a Hollowwhatever V2 once which came loose on the NDS and removed another from a bike that had virtually no use where the connecting tube was covered in rust along with the various spacers. That to me was pretty crap.
Regarding the question, I'm of the belief what Jobst Brant says "Lubricating the spindle for assembly assures a predictable press fit for a given torque. Without lubrication the press is unknown and galling (aluminum transfer to the steel spindle) may occur during assembly.
" - in my basic engineering world and why I do it is that the lube only serves to momentarily reduce friction during assembly only; the result being a crank that sits well on the axle and doesn't fall off.
We are on 10 pages now...can't believe I'm doing this but it is snowy outside....do I go up a notch on the Retrobike pecking order
Favorite quote on Retrobike:
Not worth the petrol to take it to the tip so it's down to the angle grinder to make it small enough to put in the wheely bin.