the real jig clamped onto a drysuit neck

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Rebuilding a 3D-printable drysuit repair tool as editable CAD — and getting the size wrong until I had the real file.

Reverse-Engineering a Drysuit Repair Tool

A backing plate, a split ring, and a small lesson about reference files.

A drysuit's neck seal is a stretchy rubber gasket. When it tears you glue in a new one — and you need a rigid form to press the new gasket flat against the suit while the glue cures. Someone shared a printable jig for exactly that: a backing plate and a ring that clamp the gasket between them (those clips around the rim in the photo). I rebuilt it as clean, editable CAD, driving an AI agent in Fusion 360.

It started wrong. I couldn't get the maker's design files — they were behind a login — so I sized the parts from photos. I made the plate 10.5″, the size of the factory tool it's based on. But the maker's is 9.5″. Once I had the real file emailed to me, the fix was one edit: because the model is parametric, changing four numbers re-snapped the whole thing to exact. Then I thickened it to 0.5″ and rounded every edge, so nothing sharp touches the rubber.

top-down render of the plate and split ring — Plate with finger holes; the ring split into two halves that butt together.

Same lesson as the ski connector, cheaper this time: the reference file is the truth, and guessing from photos costs a rebuild. The save was that the model was parametric — so the correction was free.