A new part was needed to fix a Vfit rowing machine where its rear leg is hand-fastened to a welded bolt after folding out. The original M8 x 20 crosshead bolt welds to the inner metal frame of the leg. After unfolding, it seems that forgetting to fasten the screw handle nut during use and resting the leg on the loose bolt results in excessive sheer force that pops the welded bolt off.

As an alternative to re-welding, a standard hex M8 x 20 bolt could be used together with this print to fix the issue. The assembled bolt and printed model will fit snugly inside the rear leg. The dimensions will be intentionally tight so the bolt/print both bind together and to the inside metal frame of the leg.

Thingiverse link of part designed

Possible Customisations

By default, the printed part itself is approx 47.3mm x 10mm x 30mm. This fits the Vfit rower exactly but the sizes can be changed online using customiser feature to suit alternative bolts. The included OpenSCAD source file includes a debug mode to view the primitive and intermediate geometry should there be a need to customise further.