Built by a Millwright · For the Trade

Every Tool You Need On The Floor & Off The Clock

Precision calculators, apprentice study tools, and trade references built specifically for industrial millwrights. No fluff. No guessing. Just results.

12 Free Calculators
4 Apprentice Year Guides
100% Trade Verified
GM Plant Tested

Live Calculators

Real calculations millwrights use every day on the shop floor. Enter your values and get instant results.

⚙️
RPM & Pulley Speed
Driven Pulley Speed
RPM

How It Works

Driven RPM = (Driver Dia × Driver RPM) ÷ Driven Dia

Use this to find the output speed of a belt-driven shaft when you know the driver pulley size, driver speed, and driven pulley size.

Common Motor Speeds

  • 2-pole motor 3600 RPM
  • 4-pole motor 1800 RPM
  • 6-pole motor 1200 RPM
  • 8-pole motor 900 RPM
⚡ Always verify belt type and tension before running. Underspeed or overspeed can damage bearings and equipment.
🔩
Gear Ratio Calculator
Gear Ratio
: 1

Gear Ratio Basics

Ratio = Driven Teeth ÷ Drive Teeth
Output RPM = Input RPM ÷ Ratio
  • Ratio > 1 Speed reduction
  • Ratio < 1 Speed increase
  • Ratio = 1 1:1 (same speed)
  • Higher ratio More torque
📐 Count gear teeth carefully — one tooth off changes the entire ratio. Use a reference mark and count twice.
🔧
Bolt Torque Calculator
Recommended Torque
ft-lbs

Torque Reference

T = K × D × F
K=nut factor, D=diameter, F=clamp load

Grade ID Markings

  • Grade 2 No marks
  • Grade 5 3 radial lines
  • Grade 8 6 radial lines
  • Class 10.9 10.9 stamped
⚠️ These are general reference values. Always follow OEM torque specs for critical machinery fasteners.
🌡️
Thermal Expansion
Change in Length
inches

Why This Matters

ΔL = α × L × ΔT
α=coefficient, L=length, ΔT=temp change

Critical for shaft alignment on hot equipment. A shaft that's cold-aligned may misalign significantly at operating temperature.

  • Pump shafts Check at temp
  • Couplings Add thermal gap
  • Pipe anchors Allow expansion
  • Gearbox mounts Check cold offset
🎯 For precision alignment work, always get operating temperature readings from the equipment operator before aligning.

All Available Tools

Everything in one place. More tools added regularly based on real shop floor needs.

Free
⚙️
RPM Calculator
Belt & pulley driven speed
Free
🔩
Gear Ratio
Teeth count to ratio
Free
🔧
Bolt Torque
Grade-based torque specs
Free
🌡️
Thermal Expansion
Material length change
New
📐
Shaft Alignment
Tolerance checker
Free
🔄
V-Belt Length
Center distance calculator
Pro
🏗️
Conveyor Speed
FPM & TPH calculator
Pro
Bearing Fit
Interference fit calc
Free
📏
Unit Converter
Imperial ↔ Metric
Pro
🔑
Keyway & Keyseat
Width & depth lookup
Free
🪛
Drill & Tap Chart
Size reference lookup
Pro
💧
Hydraulic Power
PSI / GPM / HP calc

Apprentice Hub

Everything you need to get from 1st year to Journeyman. Study guides, quizzes, and exam prep — written by someone on the same path.

📚

Study Guides by Year

Structured study materials aligned to apprenticeship program requirements. Written in plain trade language.

Browse Guides →
🧪

Trade Math Practice

Timed math quizzes covering fractions, ratios, conversions, and formulas you'll face on your Journeyman exam.

Start a Quiz →
📋

Journeyman Exam Prep

Practice tests modeled after the real exam. Track your scores and identify weak areas to focus on.

Take Practice Test →
📖

Millwright Glossary

350+ terms, definitions, and abbreviations used in the trade. Searchable and printable reference.

Open Glossary →

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