R4Dry4 Replacement Knobs

thingiverse

When you live on a farm, particularly in areas where snow falls heavily, a boot dryer is an absolute necessity. A budget-friendly option is the "R4Dry4", which boasts two knobs that tend to break easily (this assumption is based on the fact that we've had two units, with their knobs breaking on both occasions, and I've witnessed similar issues in others). Having tried gluing the factory knobs without success, I decided to create my own replacements. These custom knobs are a bit more substantial than the originals. The larger of the two knobs is designed to fit snugly over a shaft featuring a notch. To make it easy to install, I intentionally crafted the stem with a small groove. I discovered that a piece of hacksaw blade was the perfect thickness to fit into the switch's groove on the dryer. I cut a 1/4" long piece from the blade and used pliers to hold it in place while heating it with a lighter. Once hot, I carefully pushed the metal piece down into the groove until it reached near the base of the stem (with the front of the knob facing downwards). As it cooled, a thin bit of plastic placed between the knob and the switch created an excellent friction fit, securing the metal piece firmly in place. *Note:* After meticulously designing the smaller D-shaped knob, I realized that there's some variation among switches on different units. This particular knob fits my dryer perfectly, while the other two I made didn't quite match up as well. To address this issue (they were slightly loose), I simply used a thin plastic bag between the switch and the knob to achieve a secure fit.