I've got a Leonard Zinn maintenance DVD on which he applies a fair amount on grease to headset cups before pressing them. I put a bit a grease on mine when I built up my current bike but, being a bit confused at the descrepancies between different sources of advice (Park don't mention greasing cups) I asked on here (well, the old site) and got lots of conflicting advice essentially split between the "it's a press fit so should go in dry", those that greased headset cups to prevent creaking (I don't know if there's any anti-corression properties for a steel frame) and those that said something along the lines of "it doesn't matter what you apply, it'll all get squished/scraped out during the pressing process".

Anyway, since I should have a nice new frame coming in the next few months I thought I'd ask again. Should I apply grease to headset cups or not, before pressing them?

Yes

Yes. I do.

I would always use either grease or better still copper slip.

Never bothered myself. Never had any problems either.

Well, copperslip makes sense as it's static contact, so not a lubing situation.

I grease everything that goes together now, every thread, bush, bearing, the lot, but only cos I keep forgetting to buy copperslip. Had too many things stuck and too many threads pick up on removal not to do it.

+1 copperslip

I use an anti-seize compound. I wouldn't slam it in dry.

Yes, grease.

I wouldn't slam it in dry.

😯

+2 for copperslip – just a very thin smear as its an interference fit unlike nearly every other part on a bike (the odd hub has inter parts), In normal engineering an interference fit would be dry (no space for any thing) but in a normal situation: the mix of materials would be considered, it would not be subjected to the conditions of a mountain bike, and you would not change the part or take it out as often as we seem to on some bikes

It's just not good practise to fit any metal to metal parts without lubrication