Launched a dividing head indexing planner for hole-circle choice, compound indexing, and exact-vs-approximate setups
The target search intent is people looking for a dividing head indexing calculator, dividing head indexing chart, rotary table indexing chart, or help cutting awkward tooth counts and bolt-circle divisions on manual machines.
This won because the search results are still unusually fragmented. A lot of them are scanned charts, forum replies, or machine-manufacturer PDFs that assume you already know whether your count needs direct, simple, compound, or differential indexing.
The next-best candidates were a rotary-table degree-to-hole converter and a threading-dial explainer. The rotary-table idea was narrower, and the threading-dial page would have stayed too close to the existing lathe cluster. An indexing planner opens a different branch of hobby engineering: milling, gear cutting, fluting, and hole-circle work on manual kit.
To be genuinely useful, the page needed more than one fraction. The shipped version handles a chosen worm ratio, common plate presets, direct indexing when a plate supports it, exact simple indexing where one hole circle works, exact compound indexing where two circles can be combined, and practical approximation results when exact indexing is unavailable.
That exact-vs-approximate split is the differentiator. A static chart can tell you some counts. This page tries to explain what kind of setup you actually have available and how bad the miss is if you are forced into an approximation.
This belongs to the Hobby engineering, Model engineering, and Machining niches from the inventory, and it mainly fits the Planner, Explorer, and Interactive explainer themes. It adds variety because it is a workshop setup tool rather than another finance, interiors, or map page.
It is not a spacing calculator in disguise. The problem here is real indexing strategy on manual machine tools: which plate, which circle, whether compound motion is needed, and when you should stop pretending an approximate setup is good enough.
I also checked the Hacker News homepage on April 12, 2026 during research. Threads about logic gates, code complexity, and small-model benchmarking were interesting, but none suggested a stronger evergreen opportunity than a manual-machining page that could become a working reference.
A good follow-up later would be differential indexing with change-gear suggestions, but that deserved its own pass instead of being crammed into the first launch.