hmm okI’ll grind down a coil soon, i don’t even know the full durability of it, tbh.
But the math here doesn’t involve the damage epic,I think that was part of the basis of the other thread, people trying to apply damage buffs to repair. This is pretty straightforward.
The spanner is doing 16k wear removed. His is an extractor spanner so on an extractor coil it’s going to get 32k.
Spanner mastery adds 50% to wear removed so 50% of 32k is 16k, and 32k +16k is 48k. As the status message indicates is ‘applied’ (again with quotes since there was no need for that much repair).
I’ll break a coil soon and see if it gets a full repair.
EDIT actually i might have some questions for @vdragon about it since I understand that coils continue to take damage after they are worn out and stop providing power or bonus effects. Which MIGHT explain what you’ve seen, if it was a one-off event.
I have no idea how to tell how much damage a coil actually has on it 
EDIT 2: the spanner does indicate 48k wear removed. This is my crafter he has no damage skills or epics of any relation.
I’m not sure, without a wear indicator or durability numbers, how to perform the check for actual full repair on a coil. If vdragon is willing to provide any info on that I’ll be happy to proceed. If not I’ll still give it a go though, I’m trying to see what I have enough of to quickly wear out some refiner coils.
Here’s somebody saying they did 189k damage on a coil: