There are several ways make a breakable sword mechanism for use on stage. Some breakable sword mechanisms are better than others as are their visibility to an audience. This breakable sword uses a small lever on its handle to activate the release mechanism which allows the custom made blade to fall apart into two sections.
Blade split disguised on the breakable sword
The blade is stable when the breakable sword is in one piece. It can be swung about without the blade accidently separating from the sword causing potential injury. The release mechanism is almost invisible to the audience.
A display sword was purchased that the designer liked and a new composite blade was made by laser cutting the required parts in 3mm steel from a CAD drawing based on the original blade. The parts of the blade were welded together to form the new blade.
The blade sections are polished by draw filing the surfaces. This is described in more detail in the Hand Polish Steel post.
The breakable section of the blade fits onto a retaining pin on the fixed blade. A thin metal collar fitted around the blade slides up over the join between the two blade sections holding both sections together.
The spring loaded collar is made of thin steel and finished the same way as the blade sections making it virtually invisible to the audience.
The collar is connected to a small actuating rod which slides in a recessed groove made in the fixed blade.
It is connected to a spring in the sword handle which pulls the collar back down the fixed blade.
When the collar springs back towards the handle the end removeable end section of the blade is no longer supported by the collar and it falls to the stage.
The release pin is built into the sword handle. When assembling the sword the collar is slid forward over the join of the blade sections and a pin in the handle drops into a hole in the actuating lever on the handle holding the collar in position over the blade split point.
When the pin is pulled out (by the actor pressing a small lever on the handle) the collar on the blade springs back from over the blade join allowing the end section to separate and fall off.
The original CAD drawings give a better idea of the layered construction of the custom made steel blade and the recessed groove built inside.