As far as i know - diadems are a bit different to helms. But what about the Crown?
Is the crown different to a helm? I tried to put the 2 piece runeword “Lore” into a crown (ort+sol) … which seemed like a nice idea for a beginning character … but it did not turn to lore, but just took the attributed of the single runes.
Nadir is Nef + Tir and Lore is Ort + Sol. Also is the helm “mechanic’s”? If so, the runeword will not work.
yes, i edited - i meant lore. and no, it was a simple socketed (2 sockets) crown in a normal HC game.
hm, or i think it was. I still have it - because 30 lightning+7 damage reduction is useful no matter what. But now i have doubts … maybe i thought it was socketed but is in fact mechanics …
Are you sure it was a grey named helm and not a blue (magical) one, with EXACTLY two sockets, not three or four? And that you socketed them in the correct order? (ort first, then sol)
I am 100% certain on the correct order - well, its only 2 runes.
but no, now i have doubts about the status of the base item. I thought it was a grey, socketed crown … but not 100% anymore, i will have to check once the servers are up again.
Do you have a screenshot perhaps?
The link can be posted using preformatted text.
From what I know, all gear that placed in Helmet slot (head gear) can be made into Ort-Sol (Lore). As long as it’s 2 socket helm (head slot)… did you perhaps put Ort + Sol into a 3 socket helm ? 
Well, i just had a brief window of “server up” and checked.
Turns out - you were right. It is a mechanics type … gotto be more attentive next time