Lawn Mower Wheel
2026-08-24 10:44 - Making
A while back the spokes on one of the larger rear wheels of my lawn mower started breaking. It was gradual, so it took quite a while for me to realize exactly what was going on. By the time I really understood, five of the six spokes were compromised somehow. At first I tried super glue plus baking soda to make a repair. Super glue is strong but brittle, and broke off rapidly. Then I tried hot plastic staples with epoxy as a filler. Well, epoxy is also pretty strong but brittle, broke quickly, and the staples pulled out easily as well. I then went through two rounds of trying to melt in 3D printer filament as a sort of weld filler. This went much better overall, but I never got a good bond between the original and filler plastic. Pictured above is the final attempt, just after re-installing the wheel, before using it. By the time I was done only one of my repaired spokes was still solid. The rest mostly had the filler plastic still attached, but not all the way across the fracture, so they provided very little structure if at all.
As previously mentioned, late last year I got a new(-to-me) 3D printer with a large build volume. It has a 300x300 mm build plate, and this wheel has a 277mm diameter at its widest point: it can fit! So I designed a replacement. It took around 18.5 hours to print, with settings intended to both end up strong and print reliably.
And here it is, intact after the first mow! I gave it eight spokes, beyond the original's six, and I made each spoke quite beefy. Only time will tell how long it lasts, but so far so good.
