Key Clip
(2016)
Built to replace the bulky climbing carabiners I used to use to carry my keys.
Free from the strict load ratings that climbing carabiners have to adhere to, I was able to design this key clip to be compact and lightweight. The key clip weighs in at just under 14 grams.
The profile of the key clip body was cut on a waterjet from a ½” thick piece of 6061 aluminum. Tapping, countersinking, and an additional slotting operation were done on a mill. Edges were radiused with a jeweler’s file and the whole part was brought to a satin finish with red Scotch Brite.
Excerpt from notebook showing thoughts on design details and some calculations for the spring gate. Equations for spring stress as well as stress-life curves for music wire springs were pulled from Machinery’s Handbook.
The spring gate was custom wound from music wire. I made a simple mandrel with the correct diameter to account for the spring-back of the material after winding. The gate went through several iterations of different wire diameters and spring configurations to get the best feeling spring stiffness.
Nearly four years later, this is still the clip that I carry my keys on every day.