The video, from Miller Knives, shows an unusual demonstration in knife-making: creating a Roman Gladius sword, like the kind gladiators would have used back in the day. The request came from a viewer, and the caption says this is his first attempt at making a sword.
He fires up the forge and places a long piece of steel in to heat. Then he hammers the hot steel to shape, constantly heating it again so that it’s malleable enough. He shapes the body and hammers out one end flat to form a broad tip. Then he takes a disc grinder to the whole piece to sand it. The result is a rough outline of a sword.
He then uses a marker to draw lines on the steel for refining, and uses a belt grinder to polish down the steel until it fits the markings. The process takes a while. He use a rasp to smooth out the edges and files down any imperfections, as well as to make beveling.
Then he marks the other end of the piece where the handle should go, and makes notches in it with a grinder. He takes that end back to the belt to shape the nooks and crannies, and drills holes in it. Everything has another pass under the grinder and some sanding.
He cuts small pieces of steel to serve as a guard on the handle, and shapes it so it fits the end of the big piece. He drills and glues the small steel pieces in place, and hammers in some pegs. Small pieces of wood are cut to make the rest of the handle, which he also glues and pegs down. Then he uses the belt grinder to make sure all the pieces are even and smooth, including the pegs. He gives the wood some polish, and the sword is done.
In a demonstration, he uses the sword on a pineapple, which it cuts in half neatly. He also cuts a water bottle into pieces, showing that for a first attempt, this is a pretty good blade.