Broke our old Crock Pot knob, so I decided to model up a replacement. It may work on other models too. Works on a 1/4" (6.35") D-shaped shaft, see the stl if you're not sure what I'm talking about. IMPORTANT -- If using Slic3r, turn on supports, but make sure 'Don't Support Bridges' is also checked. This way the recessed back will come out okay, but the D hole won't be full of support material. It needs supports because I modeled this really close to the original design, so that this knob won't stick out any farther than the original did. But if you'd like a version that doesn't need supports (that may stick out a little farther), let me know! The pictured one went on super tight, so I loosened this one up with 1/64" of extra clearance. If it's too loose you can drop a dab of glue in there so it stays put.