Description

How a Tri Scale Ruler Works

A triangular scale ruler features three faces, each carrying two scales that run in opposite directions. This gives you six different reduction scales on a single ruler. You read the scale by aligning the zero mark with your starting point on the drawing, then reading the measurement along the graduated edge.

The two colour-coded flutings (red and yellow) make it easy to identify which face you need at a glance, saving time when switching between scales during detailed drafting work.

Built for Professional Use

The ruler is made from off-white, dimensionally stable plastic that resists warping and maintains accuracy over time. The precision-engraved graduations are clear and durable, and all dimension markings are in metric for straightforward use on South African building plans and engineering drawings.

At 300mm in length, the ruler fits comfortably on any drawing board or desk. The triangular profile sits naturally in the hand and prevents rolling when placed on a flat surface.

Scale Range — No. 1 Civil Builder

No. 1 covers the most commonly used scales for civil engineering and building plans:
• 1:20 — Detail drawings, sections, and elevations.
• 1:25 — Interior layouts and detailed plans.
• 1:50 — Floor plans, elevations, and cross-sections.
• 1:75 — Medium-scale site layouts.
• 1:100 — Standard building plans and site plans.
• 1:125 — Larger site plans and overview drawings.