Machining calculations, without the clutter

Every shop-floor calculation, one place.

Machinist Companion combines everyday machining calculators, geometry solvers, threading tools, and reference data in one fast, consistent interface.

Metric + inch workflows Responsive on desktop + mobile Documented sources
Machinist Companion Fits & Tolerances calculator showing an H7/g6 clearance fit for a 30 mm basic size, with deviation, diameter, and fit-relationship results.
Calculators
Shop Geometry
Gears & Indexing
CNC Reference
Tap & Drill Data
One companion, many jobs

Built around the calculations machinists actually reach for.

Each tool uses the same compact interaction model, so moving from fit selection to a tap drill or surface-finish calculation feels immediate.

FT
Calculator

Fits & Tolerances

Choose a basic size, hole tolerance, and shaft tolerance to see deviations, limits, fit designation, and the resulting clearance, transition, or interference relationship.

H7 / g6 Clearance fit Live tolerance relationship
TD
Calculator

Tap Drill Calculator

Calculate target tap-drill diameter and compare it with practical available drill sizes.

FS
Calculator

Feeds & Speeds

Move quickly between cutting speed, spindle speed, feed, tool diameter, and related shop values.

SF
Calculator

Surface Finish

Estimate theoretical turning and milling surface finish from tool geometry and cutting parameters.

3W
Threading

Three-Wire Measurement

Support external thread measurement over wires with the values organized for practical inspection work.

HD
Calculator

Hardness Conversion

Convert between hardness scales by material family, from carbon steel to copper alloys, instead of hunting through a generic chart.

RT
Geometry

Right Triangle Solver

Fill in known sides or angles and solve the remaining geometry for setup and layout work.

Reference

And the tables you still need.

Unified, metric, and NPT tap-drill data, drill sizes, countersink and counterbore tools, plus a G & M code reference live beside the calculators.

Unified Tap Drills Metric Tap Drills NPT Tap Drills Drill Sizes Countersink / Counterbore G & M Code Reference
Machining calculators & references

Explore every Machinist Companion tool.

Jump directly to the calculator, geometry solver, thread tool, or shop reference you need.

Feeds & Speeds Advisor

A safe range to work within, not just a single number.

Describe the tool, material, and cut, and the Advisor returns a modeled starting point plus a full Machining Envelope around it — drag independently toward conservative or aggressive on RPM and feed rate, and watch the resulting values update as you go.

  • Starting point modeled from tool diameter, flutes, material, and operation
  • RPM and feed rate tune independently across the full conservative-to-aggressive range
  • Material removal rate updates live as you drag toward the cut you actually want
Machinist Companion Feeds & Speeds Advisor showing a recommended spindle speed and feed rate with an interactive Machining Envelope for tuning conservative to aggressive.
Three-Wire Measurement

See exactly where the wires sit before you ever pick up a micrometer.

Select the thread standard, size, and tolerance class, enter the actual calibrated wire diameter you're using, and get the target measurement over wires for both limits — alongside a profile that shows precisely how the three wires sit against the thread flanks.

  • Best theoretical wire size calculated automatically, with the practical range shown alongside it
  • Target measurement over wires for both the maximum and minimum pitch diameter
  • An idealized thread profile shows exactly how each wire contacts the flanks and sits proud of the crest
Machinist Companion Three-Wire Measurement calculator showing target measurement over wires for a 1/4-20 UNC 2A thread, with a diagram of the three wires against the thread profile.
Gear Geometry

From tooth count to a complete shop plan, in the same breath.

Enter the tooth count, pitch system, and pressure angle, and Machinist Companion turns it into the numbers a shop actually needs — blank diameter, cutter setup, and inspection span — alongside a dimensioned reference drawing of the tooth form.

  • Blank outside diameter, pitch and root diameter, and full-depth infeed in one pass
  • Suggested span count and theoretical span, ready to hand off to span measurement
  • Reference drawing toggles between pitch, outside, base, and root diameter
Machinist Companion Gear Geometry calculator showing a shop plan for a 24-tooth, 10 diametral pitch spur gear alongside a dimensioned reference drawing.
GD&T Reference

A feature control frame, decoded compartment by compartment.

Break down any feature control frame to see what each compartment means, then look up any of the twelve standard geometric controls for a plain-language explanation of what it controls, how to picture the tolerance zone, and how a machinist actually checks it.

  • Quick anatomy reference for reading a feature control frame left to right
  • Plain-language "what it means," "how to picture it," and "machinist's view" for every control
  • Built-in true position / bonus tolerance check for MMC and LMC callouts
Machinist Companion GD&T Reference showing the feature control frame anatomy and a grid of the twelve standard geometric controls.
Designed for the way the shop works

Fast enough to use between operations.

01

Immediate results

Inputs and results stay close together. Most calculations update as you work, with no multi-step wizard between you and the answer.

02

Consistent interface

The same visual language carries from calculator to calculator, reducing the friction of switching between unrelated shop tasks.

03

Shop-friendly units

Metric and inch workflows are treated as first-class use cases rather than an afterthought.

04

Works at the machine

The responsive layout is designed to remain usable on a desktop, tablet, or phone without burying the important numbers.

Sources & scope

Useful calculations should show their homework.

Machinist Companion includes source and scope information alongside its technical tools. Reference data and implemented standards can be traced instead of being presented as unexplained numbers.

Always verify critical dimensions, safety requirements, material limits, and process specifications against the governing drawing, standard, tooling documentation, or qualified engineering source.

Documented data provenanceTechnical sources are identified inside the application.
Scope shown with the toolSupported ranges and assumptions are surfaced where they matter.
References kept separate from calculatorsLookup data remains easy to find without muddying calculation workflows.
Machinist Companion

Less searching. Less re-entering. More time making the part.

Open Machinist Companion