Sorry to ask yet another question.

I had bought a Dwarven Bow from the Drunken Hustman a while ago in the game (several days now), but never receieved a letter from any courier yet. Is this a bug, or does the quest not always trigger when you purchase a Dwarven artifact?

Again, any help is appreciated.

I noticed this as well... During my first playthrough I received a letter soon after finding a dwemer helmet in a random chest loot.

In my successive playthroughs I didn't receive it anymore despite he always mentions it the first time I go meet him.

it is totally random.
e.g. i bought a dwarven ingot from merchant. Then 1hour later, a courier comes

I can buy about/find about maybe 1 to 1000 of another dwarven thing and the courier may or may not come. I prefer he doesnt come, its too annoying. Besides, why would i give calcelmo a dwarven item for....i dunno 50gold???? I can sell that for 200+

in short, just drop the note.

My last character it was random, I just started buying every Dwemer piece I could and the courier showed up shortly after.

Ah, okay. So it triggers randomly. That's a relief; I was concerned I ran into a bug or something.

Thank you all!

What letter is this? Ive never had a letter from Calcelmo.

When you buy/find a dwarven weapon/item/armor piece there is a chance Calcelmo will send a letter requesting to buy it, but it's usually not worth it.

Seconded. I only found a note on a bandit once from someone (not Calcelmo), asking them to plunder the dwemer ruin and bring it to him for gold. It's not an official quest as it didn't appear in my list, but I probably could get gold for bringing dwemer artifacts. Haven't followed up on that one yet 'though.