I recently picked up an old RotoZip that was missing the guide and since those parts are no longer available I decided to create my own. This is my first attempt at Tinkercad but it actually turned out pretty good. I made 2 different versions of the foot, one flat and one with rounded edges. I printed these in PLA+ with 70% infill to make them sturdy. No supports or brim needed. The small screw on the attachment is just a 6/32 x 1" machine screw, nut and washer and and the guide adjustment screw is a 1/4-20 x 1" with a generic knob to fit. All hardware is available at your local hardware store for less than $6.00.