Tolerance Master vs DatumLab

Tolerance Master is a limits-and-fits workspace for mechanical design, machining, inspection, and education. Based on the ISO 286 and GB/T 1800 tolerance systems, it connects direct lookup, inverse fit selection, visual checking, and saved results in one focused workflow. LIMITS & FITS • Basic sizes greater than 0 and up to 3150 mm • Common hole zones A–ZC and shaft zones a–zc • Valid tolerance grades filtered dynamically by size and tabulated availability • Upper and lower deviations plus maximum and minimum limit sizes • Minimum and maximum clearance with clearance, transition, or interference classification • Switch results between micrometres and millimetres SOLVE FROM THE TARGET • Enter the clearance or interference range you need • Rank standard H-basis combinations deterministically • Compare candidates and return one to the main calculator for verification • Start quickly from preferred fit combinations VISUAL AND TRACEABLE • See the zero line, hole and shaft tolerance zones, and clearance range together • Save up to 100 calculations locally and restore them in one tap • Share a structured text summary of inputs, deviations, limits, and fit type • Move between Calculator, Fit Guide, and History workspaces Standards data and calculations run on device. Engineering inputs and saved history are not uploaded. This app is an engineering aid and does not reproduce the standards. Before critical design or production release, verify the applicable standard edition, drawing requirements, material, process, and inspection method. This app includes a 3-day local trial. Continued Pro access requires a separate monthly subscription purchase. A purchased subscription renews automatically unless cancelled in your Apple account settings. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

DatumLab is a practical mechanical toolbox for machinists, CNC operators, mechanical designers, and shop-floor technicians. Use it to look up common thread data, calculate ISO fits, estimate speed and feed values, convert shop units, check material references, and save frequently used setups. Core tools work offline, so you can keep working at the machine, in the workshop, or during design review without depending on a network connection. Key tools: Thread calculator for metric, UNC, UNF, BSP, NPT, trapezoidal, and Heli-Coil references Tap drill, clearance hole, pitch, pitch diameter, and minor diameter lookup ISO tolerance and fit calculator for common hole and shaft zones Speed and feed calculations for milling, drilling, tapping, and turning Radial chip thinning and thread turning helpers Unit conversion for length, pressure, torque, speed, force, and mass Material references for common aluminum, steel, stainless, non-ferrous, and plastic materials Weight, bolt preload, and geometry helpers Favorites, recent calculations, custom tools, custom materials, and exportable reports DatumLab is designed for quick reference and setup planning. Values are reference starting points only. Always verify final machining parameters with your tool, machine, workholding, material, and supplier recommendations.