What you were expecting to happen, and what actually happened?
Mechanist perk “Power Armor” does show your hero as a construct, but does not gain double attack and double armor when sparkgrinder performs his skill.
Currently, all hero class perks do not work for troops that change their ability based on troop type. I forget if they mentioned if it will be fixed in 2.0 or not.
machinist is supposed to get a different 3rd trait… i read it wasn’t supposed to be released yet but it was done because of “spring imp” issues the 3rd trait isn’t available in 1.9 but is in 2.0