Homemade Knife-Throwing Machine

Bad action movies make it look easier than it is to throw a knife and make it stick in a target. After seeing those movies, Quint and his son got the idea to build a machine that can throw knives from a magazine to any point within its range.

It’s not hard to use a machine to throw a sharp piece of metal, but it takes skill to time the spin so that the piece lands point-first on the target. Quint did this by using a pair of high-performance servo motors to drive two timing belts that were lined up next to each other. A spinning throw can be made by putting a knife holder on the carriage between the belts and running one belt a little faster. A set of copper rails holds up the carriage, and a few used carbon motor brushes move the knife holder.

At first, an electromagnet held the throwing knives in place, but it couldn’t do it all the time. This was changed with a mechanism that is powered by a solenoid and locks into grooves cut into the knives. As long as the trigger is held down, knives are fed by a spring-loaded magazine in the back. This makes it a full-auto weapon. A LIDAR sensor measures the distance and changes the angle of the targeting laser to match the trajectory of the knife with the speed at which it spins. The process of making something new was full of risk, failure, and frustration. Some of the problems were unstable knife holders, carriages that blew up, and broken gadgets that seemed to fire on their own. But in the end, they made a machine that can throw knives and get kids interested in programming and making things.

Melody Joy “Montana Hale” Cuenca, who was showing these techniques at the SOG Knives booth, taught me how to throw knives and tomahawks at the SHOT Show’s Media Day at the Range earlier this year. Melody is a smart and talented woman with a lot of education. Melody and her husband, John “TJ Quicksilver” Cuenca, are known in the world of blade fighting as the Quicksilvers. Melody just set two world records and won the 2014 Women’s World Knife and Axe Throwing Championship in France. Even though Melody gave me some tips that helped me throw knives and tomahawks like a badass, my DIY brain was drawn to the wooden target they had set up at the booth to throw knives and tomahawks into. Since I’ve wanted to learn this method for a long time, I knew right away that I wanted to build my own to practise with and that it would be a great DIY to share on ITS. 

Making it Easy to Throw Knives at a Target

The design of the target is simple, but I had to get a little creative because I didn’t have any real plans to work from. I had a few pictures of the target from Range Day, so I was able to figure out the sizes quickly. I hope you enjoy putting this do-it-yourself project together as much as I did. It’s easy and cheap to do.