Knobs for chinese cobbler patcher shoe repair machine

thingiverse

Knobs for your no-name Chinese patcher sewing machine can be easily upgraded. These machines come partially assembled, which is a good thing because I can customize them in many ways. To print these upgrades: Print exactly as the STL files are designed. Use 100% infill to ensure maximum strength. No support material is needed if you print in the direction indicated by the STL file. The knobs are designed with gentle slopes that allow for printing without support, even if your slicer suggests otherwise. Don't use support; it will only cause problems. The nuts and bolts on these machines are metric-sized, mostly M6. Adding washers to many parts can improve performance, and finding M-washers is the best option. To secure the knobs properly, you need to heat the nuts before pressing them onto the pieces. Without heating, the holes are too small for easy installation. An M6 washer behind the tension knobs can provide smoother operation. The stitch length bolt operates in a narrow range - about 1/4 turn from short to long. Some users may not realize its purpose due to this limited range. To assemble it properly, pass the bolt through the knob, then place a thin washer on top, followed by a spring. The whole assembly should be securely compressed. A bonus upgrade is the center-cap.stl file, which creates a small cap that snaps onto the rotation wheel's large nut. This design assumes you'll use a compression washer underneath - highly recommended. I've printed several versions with different designs, but only one is included here. These upgrades are designed with PLA filament expansion in mind, but if your printer prints differently or uses materials that expand at varying rates, you may need to glue the nuts or scale down the knob slightly and print again for a secure fit. Have fun upgrading your sewing machine!