Triangle ruler Centrum model 80728 — drafting tool for measuring and drawing angles

The Centrum triangle ruler model 80728 is a compact drafting tool designed for drawing straight lines and measuring common angles. Made with a rigid triangular profile, this instrument helps guide pencils and pens to produce accurate strokes for schoolwork, office tasks and basic technical sketches. Its lightweight construction and slim form make it easy to store in pencil cases or carry in a bag for on-the-go use.

Advantages

The triangle ruler offers stable edge guidance for precise line drawing and angle alignment without flexing during normal use. Its triangular shape provides multiple straight edges and fixed angle references, allowing quick switching between directions. The simple design ensures low maintenance and long usable life under typical classroom and office conditions.

Suitable for

• School geometry exercises and technical drawing lessons
• Office tasks requiring straight lines or layout sketches
• Basic drafting and hobby sketching
• Measuring and checking common angles in non-specialized applications

Key specifications

• Triangular rigid profile providing multiple straight edges
• Lightweight construction for easy handling and portability
• Slim form factor suitable for pencil cases and document folders
• Suitable for use with pencils and pens for manual drawing

How to use

Place the triangle ruler on the drawing surface with the desired edge aligned to the points you wish to connect. Hold the ruler firmly to prevent shifting, then draw along the chosen edge with a pencil or pen. To measure or construct angles, align one edge with an existing line and use the appropriate adjacent edge as the angle reference. Store the ruler flat or in a pencil case when not in use to avoid warping.

Usage recommendations

For best results, use a sharp pencil or a technical pen with a fine nib and apply even pressure while drawing. Avoid exposing the ruler to high heat or heavy weight to maintain its straight edges. Clean with a soft cloth if debris accumulates along the edges.