# MachineCalcs Agent Guide MachineCalcs is a public, no-login collection of mechanical and machine-design calculators that show their formulas, assumptions, reference data, and supporting guides. ## Discovery - LLM index: https://machinecalcs.com/llms.txt - Public calculator API: https://machinecalcs.com/api/calculators - OpenAPI: https://machinecalcs.com/.well-known/openapi.json - API catalog: https://machinecalcs.com/.well-known/api-catalog - Agent skills index: https://machinecalcs.com/.well-known/agent-skills/index.json - MCP server card: https://machinecalcs.com/.well-known/mcp/server-card.json - Auth notes: https://machinecalcs.com/auth.md - Sitemap: https://machinecalcs.com/sitemap-index.xml ## Calculator Hubs - [Springs calculators](https://machinecalcs.com/springs-calculators): 11 tools - [Gears calculators](https://machinecalcs.com/gears-calculators): 16 tools - [GD&T calculators](https://machinecalcs.com/gdandt-calculators): 8 tools - [Machining calculators](https://machinecalcs.com/machining-calculators): 22 tools - [Materials calculators](https://machinecalcs.com/materials-calculators): 3 tools - [Hydraulics calculators](https://machinecalcs.com/hydraulics-calculators): 13 tools - [HVAC calculators](https://machinecalcs.com/hvac-calculators): 7 tools - [Electrical calculators](https://machinecalcs.com/electrical-calculators): 3 tools - [Power Transmission calculators](https://machinecalcs.com/power-transmission-calculators): 16 tools - [Automotive calculators](https://machinecalcs.com/automotive-calculators): 34 tools - [Aviation calculators](https://machinecalcs.com/aviation-calculators): 26 tools - [Electromechanical calculators](https://machinecalcs.com/electromechanical-calculators): 5 tools - [Fasteners calculators](https://machinecalcs.com/fasteners-calculators): 16 tools - [Sheet Metal calculators](https://machinecalcs.com/sheet-metal-calculators): 3 tools - [Structural calculators](https://machinecalcs.com/structural-calculators): 13 tools ## Highest-Value Tools - [Compression Spring Calculator](https://machinecalcs.com/compression-spring-calculator): Rate, Wahl-corrected stress, solid height and buckling, with built-in material data. - [Spring Design Calculator](https://machinecalcs.com/spring-design-calculator): Back-solve wire diameter and active coils from target load, travel, diameter and spring index. - [Spring Force Calculator](https://machinecalcs.com/spring-force-calculator): Compression spring force from deflection, with stress, solid height and buckling checks. - [Spring Deflection Calculator](https://machinecalcs.com/spring-deflection-calculator): Compression spring deflection from load, with stress and travel-to-solid checks. - [Spring Wire Size Calculator](https://machinecalcs.com/spring-wire-size-calculator): Solve required compression-spring wire diameter from target rate, then check stress and travel. - [Music Wire Spring Calculator](https://machinecalcs.com/music-wire-spring-calculator): ASTM A228 music-wire spring rate, force, tensile strength and corrected stress. - [Spring Index Calculator](https://machinecalcs.com/spring-index-calculator): Spring index C = D/d with mean, inside and outside diameter conversion. - [Spring Rate Calculator](https://machinecalcs.com/spring-rate-calculator): Spring rate (spring constant) from wire size, coil diameter and material. - [Extension Spring Calculator](https://machinecalcs.com/extension-spring-calculator): Rate, spring index and force at extension including initial tension. - [Spring Constant Calculator](https://machinecalcs.com/spring-constant-calculator): Spring constant from two measured load/deflection points (Hooke’s law). - [Torsion Spring Calculator](https://machinecalcs.com/torsion-spring-calculator): Deflection angle, rate per turn and Wahl-corrected inner-fibre bending stress for a helical torsion spring. - [Gear Generator](https://machinecalcs.com/gear-generator): Generate an involute spur gear profile with live preview and DXF export. - [Gear DXF Generator](https://machinecalcs.com/gear-dxf-generator): Generate an involute spur gear DXF for CAD/CAM from module or diametral pitch. - [Spur Gear Calculator](https://machinecalcs.com/spur-gear-calculator): Spur gear geometry, undercut warning, center distance and DXF export. - [Involute Gear Calculator](https://machinecalcs.com/involute-gear-calculator): Tooth geometry from module/DP and pressure angle, with a tooth-profile render and DXF export. - [Gear Tooth Calculator](https://machinecalcs.com/gear-tooth-calculator): Involute spur gear tooth thickness, addendum, dedendum, whole depth and undercut margin. - [Gear Ratio Calculator](https://machinecalcs.com/gear-ratio-calculator): Gear ratio with output RPM, torque and vehicle speed from tire size. - [Gear Center Distance Calculator](https://machinecalcs.com/gear-center-distance-calculator): Spur gear center distance from module/DP and two tooth counts. - [Gear Pitch Calculator](https://machinecalcs.com/gear-pitch-calculator): Convert module, diametral pitch and circular pitch, plus pitch diameter. - [Pitch Diameter Calculator](https://machinecalcs.com/pitch-diameter-calculator): Gear pitch diameter from module, DP or circular pitch and tooth count. - [Gear Module Calculator](https://machinecalcs.com/gear-module-calculator): Module from pitch diameter and teeth, with diametral and circular pitch. - [Gear Tooth Ratio Calculator](https://machinecalcs.com/gear-tooth-ratio-calculator): Single- or two-stage gear-train ratio and output speed from tooth counts. - [Planetary Gear Calculator](https://machinecalcs.com/planetary-gear-calculator): Epicyclic gear ratio for ring-, sun- or carrier-fixed arrangements. - [Worm Gear Calculator](https://machinecalcs.com/worm-gear-calculator): Worm drive ratio, center distance, lead angle and self-locking check. ## Guides And Reference Data - Guides: 19 explanatory engineering pages linked from https://machinecalcs.com/guides - Reference charts: 27 tables linked from https://machinecalcs.com/#charts ## Use Policy For Agents - Public calculators, guides, reference charts, sitemap, and llms.txt may be crawled. - Search and real-time AI answer grounding are allowed. - Model training is not granted by the robots.txt Content-Signal preference. - No account, OAuth flow, API key, or agent registration is required for public pages. - Results are engineering references and are not a substitute for professional review on safety-critical designs.