My grandfather has a beloved Black and Decker under-counter can opener that is probably as old as my stepdad. It finally broke, and my grandfather was devastated. Something had to be done.

My stepdad identified that a little lever piece used to engage the opener had broken. I offered to make a replacement. To make my initial sketch, I traced a scaled image of the original part. For this replacement piece to work and not just fit, I had to consider how it was actually going to be used in the machine. This part included three additional design constraints:

1. It had to act as a spring.
2. It had a pin that experiences a perpendicular load.
3. It had a small feature extruded on both sides.

To allow the piece to flex more and act as a spring, I chose to print it in PETG.

If I had printed the pin in PETG, it would have immediately snapped along the layer lines due to the bending force applied to the pin. Instead, I cut a small section of a coat hanger and heated it up to insert it into the part. The force is now distributed between layers.

To account for the small features being extruded on both sides, making printing flat on the bed difficult, I split the back extrusion into a second small piece that could be glued in. I keyed it to help the glue resist the rotational force that piece experiences.

Two years later and it’s still going strong!