A workshop, not a fitting quiz

Club Builder Lab is a browser-based clubmaking bench for DIY builders, gear nerds, hobby repairers, and small shops. It is not a swing-fitting recommendation engine. You measure a finished club, or you assemble a model from components, then you watch length, balance, and Lorythmic swingweight move on a schematic in real time.

Search traffic often lands on a swing weight calculator or a lead tape calculator. Those pages stay simple on purpose. The moment you need position-based tape, shaft trims, what-if scenarios, or a set trend, one control hands the same physics into this lab. One calculation core feeds the bench, the charts, the PDF sheet, the calculators, and the set matcher.

Measure, then model — never mix the badges

The highest-confidence path is Mode A: weigh the club, find the balance point from the butt, enter playing length. The engine reports first moment about the 14-inch fulcrum and maps it onto the Lorythmic scale. Scale and balance tolerances propagate into an estimated swingweight range, because a ±1 g postal scale and a ±1/8" balance read are not the same as a dedicated swingweight scale.

Mode B is a component stack: head, shaft, grip, ferrule, adapter, tip weight, lead tape, extension. Every part is a mass and a station from the butt. Predicted numbers wear a MODELLED badge. Measured numbers wear MEASURED. A set can mix clubs of both kinds, but a single result never pretends a model is a scale reading.

What-if, reverse solver, set repair

Keep a baseline build, then fork Scenario A/B/C — shorten half an inch, drop four grams of grip, add four grams at the head. The reverse solver looks for small legal moves toward a target swingweight. Set Match charts length, total weight, and swingweight, then flags clubs that leave your trend, not a generic “D2 is best” slogan. One click opens the outlier on the bench.

Projects, component library, and inventory live in IndexedDB on this device. Export JSON and CSV whenever you want. There is no account and no cloud lock-in.