While I’ve got you here, do you have any thoughts about door knockers? There’s the idiom avāpuraṇaṁ ādāya, which is usually translated, “taking a key”, spoken as part of making an announcement. I’ve never seen an explanation of why you’d use a “key” to make an announcement, or indeed, any reason to think that anyone, especially monks, would have a sophisticated thing like a lock and key.
Another idiom is where someone knocks on the door of a hut, where we find, aggaḷaṃ ākoṭesi. I wondered why they were said to knock specifically on the latch (aggaḷa), but then it occurred to me that they were probably knocking with the latch. If it was a sizeable bolt-type thing, it seems to have doubled service as a latch and a door-knocker.
In Ss2, we have (your translation):
avāpuraṇaṃ ādāya ghaṭikaṃ ugghāṭetvā kavāṭaṃ paṇāmetvā vihāraṃ pāvisi.
Udāyī took the key, unlatched the bolt, opened the door, and entered the dwelling.
I wonder whether avāpuraṇa and ghaṭika are parts of the aggaḷa? Or are they just different things? Or different terms for the same thing?
In any case, combining the two cases suggests that, just as the aggaḷa was used as a knocker, the avāpuraṇa was used in the same way, except it was obviously detached. Maybe it was just a bolt that was knocked against a block of wood or bell of some sort.