Technical Compass Grand GR-C204 (model 237099) — drafting instrument for precise circles and arcs

Grand GR-C204 technical compass is a drafting instrument designed for drawing precise circles and arcs in technical drawing, geometry and design tasks. The compass features an adjustable span that allows users to set a wide range of radii and a stable pivot point to minimise slip during use, making it suitable for paper and drafting board work. The construction balances rigidity and fine adjustment to provide repeatable results when laying out geometric constructions or scale drawings.

Advantages

The compass offers a precise adjustment mechanism for accurate radius setting and consistent line quality. Its stable pivot and secure lead holder reduce wobble and unintended movement, improving reproducibility of circles and arcs. The materials and joint design provide durability and steady tension, while the ergonomic shape supports comfortable handling during extended use. The tool is compact and portable for classroom, studio, or site work.

Suitable for

• Technical drawing and drafting
• Geometry exercises and educational use
• Architectural and engineering sketches
• Hobbyist model-making and design
• Paper-based measurements and layouts

Key specifications

• Adjustable radius range suitable for a variety of circle sizes
• Stable pivot point for accurate centring and rotation
• Fine adjustment mechanism for precise setting of span
• Secure lead/pen holder compatible with standard leads or technical pens
• Durable joint and arms designed for steady tension and minimal play
• Compact form factor for portability and storage

How to use

Fix the pivot point at the desired centre and set the span to the required radius using the adjustment mechanism. Insert a sharpened lead or compatible technical pen in the holder and ensure it is secured to the same height as the pivot tip. Place the pivot tip firmly on the drawing surface and rotate the arm smoothly to draw a circle or arc, keeping consistent pressure to maintain line quality. For repeatable results, check tension at the joint and readjust the span before each use.

Usage recommendations

Store the compass in a protective case or sleeve to prevent damage to the pivot and lead. Use a clean, flat drawing surface and a sharpened lead for the best line clarity. Regularly check and tighten the adjustment mechanism if you notice play in the joint.