Slingshots can be fun, and are usually very simple devices. Usually, a length of stretchy rubber is attached between a y-shaped structure, then pulled and released to launch whatever object you decided to put in the ammunition pouch. This slingshot build, by Eric Au of Metro Grade Goods, takes things one step further by adding homemade bearings for the rubber to rotate on while flinging the projectile.
The theory is this: Since the forks can rotate, they will eliminate some of the friction produced as the rubber rapidly moves. These rotating forks are made by machining two pieces of 5/8-inch aluminum on a lathe, leaving a groove in the center. A 1/4-inch hole is drilled through the middle, then countersunk to accommodate the machine screws. This gives everything a nice, finished look.
Even ignoring the rotating feature, the slingshot is quite well made. The wooden structure was cut out initially, then given a generous chamfer for better ergonomics. The wood was dipped in boiled linseed oil for 25 minutes and given 2 coats of polyurethane for an excellent finish. If you’re wondering how well this device works, be sure to check out the videos below.
This isn’t Au’s only slingshot creation. He also made an interesting model using acrylic plexiglass.