NOTE9 JUNE 2026 — WENZHOU — HENRY, EYEFIY
Where the force goes
A hinge that clamps acetate with one screw on a small face will loosen. Two redraws fix it — and the better one moves the load off the end piece entirely.
弹根胶链与对口胶链并排微距：两种铰链都打开 90°，浅景深突出结构差异；下面垫图纸或牛皮纸。能配上单颗螺丝夹板材的问题件实物更好。
手机实拍即可 · 不修图 · 全清单见 site/ASSETS.md
One screw. Clamping acetate. On a face too small for the job.
That structure loosens. Not might — does. The screw is fine. The acetate face it bites is the problem: too little material under load, too much leverage on it. Open and close the temple enough times and it starts to wander.
We flagged the structure this week and redrew it two ways.
Redraw one: extend the clamping face up and down, run a crossbar between, and set two screws instead of one. More material under load. Load shared across two fasteners. It works.
Redraw two is the better answer: replace the butt hinge with a spring hinge. A spring hinge does one quiet job — it unloads. The opening force lands inside the hinge mechanism instead of in the end piece. The acetate stops being a structural part and goes back to being a shape.
Most loose-temple problems get treated with a screwdriver. Tighten, return, tighten again. The screw was never the problem.
The drawing changed before the next run. Nobody will complain about a hinge they never felt loosen — which is the only kind of QC result we are after.
The structure decides where the force goes. The force decides what fails.