Guides / Process

What Your Custom Gear Drawing Must Show

November 1, 2026

A normal part drawing shows geometry. A gear drawing also needs a data table, because the tooth shape is defined by numbers rather than by lines. Without that table, a shop has to guess or ask, and the quote waits.

The gear data table

Data	Why it matters
Module or diametral pitch	Size of the teeth
Number of teeth	Together with module, the pitch diameter
Pressure angle	20° is standard, 14.5° on older machines
Helix angle and hand	Helical gears only
Profile shift	Changes tooth thickness and center distance
Quality class	AGMA, ISO or DIN, decides the process
Measurement over pins or span	How the shop checks tooth thickness

Material and heat treatment

State the material grade and the hardness after treatment. For case hardened gears, also state the case depth. Heat treatment moves the teeth, so a high class after case hardening usually means grinding.

Blank and bore

The teeth are only part of the gear. Show the bore with its tolerance, the keyway or spline, hub dimensions, face width and the faces that must run true to the bore.

Checks you want

Say what you need on the report: tooth thickness, runout, hardness, or full profile and lead charts for precise gears. Asking for more inspection than you need adds cost.

Checklist before you send

1. Gear data table complete
2. Material and hardness
3. Bore, keyway or spline with tolerances
4. Quality class or application
5. Quantity now and per year
6. Photos of the old gear if this is a replacement

With these six items most gear requests get a firm price in the first reply.

Frequently asked questions