The interactive handbook for the physical world.

Enter a designation or a measurement — a drill number, a thread callout, a diameter — and get the exact dimensions, the recommended tap drill, and the nearest standard sizes. No category to choose first.

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Reference tools

Nearest Drill Size Finder Measured 6.7 mm? See the closest metric, fractional, number, and letter drills — with the exact difference for each. Thread Decoder Enter 1/4-20 or M8×1.25. Get dimensions, pitch, tap drill, clearance holes, and drill alternatives. Universal Drill Size Chart 309 standard drills — fractional, number, letter, and metric — in one sortable, printable table. Tap Drill & Clearance Chart 65 UNC, UNF, and ISO metric threads with recommended tap drills and clearance holes.

What BenchReference is

A permanent reference utility for physical standards: identify → decode → dimensions → nearest standard → compatible tool or part. Every value is structured data tied to a recognized standard — ASME B94.11M drill sizes, ASME B1.1 unified threads, ISO 261 metric threads, ISO 273 clearance holes — with deterministic conversions and no editorial filler. A drill diameter doesn't change; neither should the page that documents it.

Current coverage: 309 standard drill sizes across four systems and 65 thread standards with tap-drill and clearance relationships. Pipe/NPS, O-rings (AS568), and bearings are planned next.