Stiga SB40 Trimmer Spool Head

thingiverse

Repair part for the wire spool of a Stiga SB40 Brush Cutter / Grass Trimmer. The original is made from plastic, and eventually its surface wears down to almost nothing and it falls out or disappears altogether. When that happens you'll have a large hole in the head that scoops up dirt rather than pressing the internal spring to release more thread. I had to either buy a completely new head or repair the spool holder. Guess what? I chose the latter using my home-built RepRap. Print Settings Printer Brand: RepRap Printer: Prusa i3 Rafts: No Supports: Doesn't Matter Resolution: 0.5 mm nozzle, 0.2 mm layer height Infill: 35% Notes: Printed with ABS. If you don't print a solid part (100% infill) you may want to consider at least 2 mm solid top and bottom layers and thick shells to slow down wear. Post-Printing Assembly Disassemble the trimmer head, take out the spool holder, and wipe away any dirt or dust. Cut out the sprocket-like center of the spool holder (if it hasn't already fallen out) and cut away the remnants so you get a clean sprocket-like hole. Print the replacement part and check if it fits by placing it upside down in the hole that you previously prepared. If necessary, adjust any of the two parts with a Stanley knife. When you're happy with the form fit, insert the replacement part into the bottom. Make sure it's positioned well enough to go all the way down and come out at the end: It will be hard to rotate once inside. Use a vice to press the replacement part all the way through until it comes out at the end. Assemble your spool holder, and you're done. How I Designed This FreeCAD The shape is straightforward. With help from online FreeCAD tutorials, I was able to create the shape I wanted within 20 minutes. Just some tweaking and a few trial prints were left before the design fit my needs.