This is a part of worldbuilding that I like. My story, Droran, the Naronian soldiers fill in their "spare time" with scheduled exersise, studies and work. "Spare time" for a Naronian soldier is the time beqtween military drills, guard duty and actual combat. One of the many "free-time" chores is to man the forgeworks, where armor, tools and weapons are made. The different decuria take turns and change shifts to constantly hold the different stations working.
On this particular picture, Haze and Kane are making thread for the ring-maille workshop. It's hard work and takes a staedy hand, but they're enjoying every opportunity to hang out and talk and joke around. The workshops are among the few places where that kind of entertainment is encouraged. It strengthens the bond between the soldiers and halps them get through the shifts effectively.

I got this idea of soldier labor during my time in Bäckedal, a craft-school dedicated to lod crafts. We got to learn how to make iron thread from a lump to a roll of thread. It was one of many awesome experiences in that school :3