How to Draw a Gear in AutoCAD: Step-by-Step Guide

To draw a gear in AutoCAD, start by creating a circle for the base, then draw one tooth shape using Line and Arc commands. Use the Polar Array command to copy the tooth evenly around the circle, forming the gear teeth.

Syntax

Here are the main AutoCAD commands used to draw a gear:

• Circle: Creates the base circle of the gear.
• Line: Draws straight edges of a gear tooth.
• Arc: Draws curved parts of the tooth.
• Polar Array: Copies the tooth around the circle evenly.

autocad

CIRCLE
Specify center point for circle or [3P/2P/Ttr (tan tan radius)]: 0,0
Specify radius of circle or [Diameter]: 50
LINE
Specify first point: 50,0
Specify next point: 55,5
ARC
Specify start point of arc: 55,5
Specify second point of arc: 52,8
Specify end point of arc: 50,10
POLARARRAY
Select objects: (select tooth lines and arcs)
Specify center point of array: 0,0
Enter number of items: 20
Enter angle to fill or [Angle between]: 360

Output

A gear shape with 20 teeth evenly spaced around a circle of radius 50 units.

Example

This example shows how to draw a simple gear with 20 teeth using basic shapes and the Polar Array command.

autocad

CIRCLE
0,0
50
LINE
50,0
55,5
ARC
55,5
52,8
50,10
LINE
50,10
48,8
ARC
48,8
45,5
50,0
POLARARRAY
(select all tooth lines and arcs)
0,0
20
360

Output

A circular gear with 20 identical teeth arranged evenly around the base circle.

Common Pitfalls

Common mistakes when drawing gears in AutoCAD include:

• Not closing the tooth shape properly, causing gaps in the gear.
• Incorrect center point when using Polar Array, leading to uneven teeth placement.
• Using too few teeth in the array, making the gear look unrealistic.
• Forgetting to select all parts of the tooth before creating the array.

autocad

LINE
50,0
55,5
ARC
55,5
52,8
POLARARRAY
(select only some tooth lines)
0,0
10
360
-- This results in incomplete teeth and uneven spacing --

Output

Gear with missing or uneven teeth due to incomplete selection and fewer array items.

Quick Reference

Command	Purpose	Tips
CIRCLE	Draw base circle of gear	Use center at 0,0 for symmetry
LINE	Draw straight edges of tooth	Snap to endpoints for accuracy
ARC	Draw curved tooth edges	Use 3-point arc for smooth curves
POLARARRAY	Copy tooth around circle	Select all tooth parts and set correct center

Key Takeaways

Start by drawing the base circle with the Circle command.

Create one complete tooth shape using Line and Arc commands.

Use Polar Array to copy the tooth evenly around the circle.

Always select the entire tooth shape before creating the array.

Check the center point and number of teeth for even spacing.