This post was a few days in the making, owing to yo-yo weather (what I call wild temperature swings, in case you didn't know) messing with my head and, by extension, my creativity. These are the first two steam-powered melee weapons I've made for the various types of sartorii.
At top is a pneumatic sabre, and at bottom is a pneumatic poleaxe. The former is the standard melee weapon of the sartorius troopers, carried along with their arm-mounted rotary cannon, but not drawn unless necessary.
The serrated blade reciprocates back and forth, while the rod above the blade remains stationary as a guide. Much like the rotary cannon, the speed of the blade is controlled by the "trigger" built into the hilt. Steam then rotates a small impulse turbine, which is connected to the blade.
The serrations don't saw through the intended target as much as they deflect defenses, such as blades or shields. Any opponent who tries to block or parry this weapon when reciprocating at full speed would find their weapon yanked and/or knocked from their grip rather violently.
The steam intake is the upper brass bit, runs through the grip, while the exhaust runs through the outer portion of the guard and out the lower brass bit. Sartorius armour is a closed steam system, i.e. one in which exhaust steam is fed back into the water reservoir and recycled. I will go into more detail about how this works in the post about the sartorius armour itself.
When not in use, the pneumatic sabre is suspended from a ring-type weapon frog by means of the small, forward-pointing quillon. The hoses are supposed to run from the brass bits on the boiler (right side of picture) through the elbow mounts (left side of picture) and to the connectors on the end of the sabre itself.
The pneumatic poleaxe is a much more powerful weapon, but also much more cumbersome, even for a warrior in steam power armour that would enable the wearer to dead-lift a car. Unlike the pneumatic sabre, there is simply no way to wear this weapon, therefore it must be carried. Sartorius troopers don't typically use these for that reason, but they are quite popular among the sartorius guards who remain at the mech-cities and other stations.
The steam intake (once again, the upper brass bit) is split in two, running through the guard, then up into the bottom of the weapon head, with each half driving a small impulse turbine, just as on the pneumatic sabre. One turbine drives the reciprocating axe blade, while the other drives a balancing piston, hidden inside the cylinder, in the opposite direction. The purpose of the balancing piston is to keep the weapon from constantly snapping back and forth in the wielder's hand from the perpendicular motion of the reciprocating head.
The exhaust comes out each side of the housing on the axe head, and runs down the sides, forming additional guards, just as on the sabre, before joining together at the exhaust port. The "trigger" runs the entire length of the grip, allowing the wielder to easily change hand positions. This is, after all, a two-handed weapon, though the range of motion is somewhat limited owing to it being tethered to the wielder by means of steam hoses.
I have a few other weapon designs along these lines in mind, and I'll share them as I make them. Tomorrow will be a busy day for me (hopefully a productive one as well), but with any luck, I'll finally finish this little project the day after, and I can move on to the next one.