Shop reference tables that are actually right

Drill Bit Size Chart

All 354 number, letter, fractional & metric jobber drill sizes: searchable, sourced, and printable.

Tap Drill Chart

All 193 tap drill sizes for 54 Unified threads, with percent thread engagement and 5 documented Handbook corrections.

NPT Thread Chart

All 24 NPT pipe thread sizes with basic dimensions, verified against their published derivation formulas.

Sheet Metal Gauge Chart

Gauges 3 through 38 for steel, galvanized, aluminum/brass/copper, Birmingham, and zinc gauge, side by side.

Bolt Torque Chart

A live torque calculator that shows its formula, plus 52 SAE and 30 metric grade/size reference rows.

Tap Drill Calculator

Pick a thread and target percent thread engagement, get the recommended tap drill and every alternative.

Thread Engagement Calculator

Enter any thread and any drill size to get the exact percent thread engagement, not just a table lookup.

Drill Size Converter

Convert any drill size between decimal inch, mm, fraction, number, and letter, with the nearest real drill in each system.

Torque Converter

Convert torque between lb-ft, N·m, lb-in, and kgf·m, with common fasteners that land in that range.