replacement gear with clutch for toy

prusaprinters

<p>My kid had a prized toy dog that rolled around when you pushed its legs down, but it stopped working right. &nbsp;I took it apart and found that a tiny clutch mechanism in the drive was broken. &nbsp;It's hard to see, but the outer circle is broken so the clutch mechanism will not grab on the inside of the bigger gear it rides in. &nbsp;But worry not, I have a Prusa MK3S+ so this little toy dog would be rolling across the floors tripping mom again in no time.</p><p>1. &nbsp;Extract the broken gear without breaking anything else</p><p>2. Photograph the gear on top of graph paper</p><p>3. Import the image into your favorite modeling software. &nbsp;I used Autodesk Inventor.</p><p>4. Scale the image using the graph paper lines as a reference. &nbsp;My lines were 0.25" apart, so I scaled the image until they measured 0.25" apart in the software.</p><p>5. Trace the edges. &nbsp;No need to draw fancy involute tooth profiles, a couple curves or a spline are close enough for a low tolerance plastic gear. &nbsp;Use a caliper to measure the shaft and outer diameter to make sure your drawing is scaled correctly.</p><p>6. Export an .STL file and open it in PrusaSlicer.</p><p>7. Slice it. &nbsp;I used “0.2 detail” settings with a 0.4 mm nozzle.&nbsp;</p><p>8. Print it. &nbsp;I used PLA, I'm sure nylon, ABS or even PETG would have been stronger, but PLA worked fine.</p><p>9. Find all the screws you dropped and re-assemble everything.</p><p>I have used this photograph, trace and print method for several things and it usually works pretty well. &nbsp;A flatbed scanner often works even better than a photo since there is no lens distortion and the scale is known. &nbsp;I doubt many will need this same part for their broken dog toy, but I wanted to share this method that can be used to copy other broken or worn out parts.</p>