Technical Drawing Tools: Set Squares, Compasses and Rulers

Geometry, design technology, architecture and fashion drafting all need clean, accurate lines. This guide explains the technical drawing tools students use most: set squares, compasses, geometry sets, drafting rulers and drawing boards, with tips on using them for neat, precise drawings.

Set squares

A set square is a flat triangle used to draw straight lines at set angles and to draw lines parallel or at right angles to each other. Set squares usually come in two shapes: one with 45° angles and one with 30° and 60° angles. Slide a set square along a straight edge to draw parallel lines quickly.

• Set Square 6435 (33cm) and the larger Set Square 6445 (43cm) for technical drawing and architecture.

Compasses and geometry sets

• Natraj Mathematical Instruments Set: a school geometry set with a compass and rulers.
• Single compasses for accurate circles: Hushang Compass 6900, Compass V90, Deli Compass VC117 and Deli Compass G30994.
• Bomeijia Compass Cutter: cuts perfect circles from paper and card for models and cards.

Drafting rulers for pattern and fashion design

• Multi Function Right Angle Ruler, Half Round Ruler and Yard Ruler: drafting rulers for patterns, curves and measurements in fashion design and sewing.

Boards, pencils and erasers

• A smooth, firm board such as the Drawing Board A3 or Drawing Board A2 (7mm thick), with the paper taped square.
• Hard pencils such as 2H for light construction lines and HB for final lines, or a Pentel 0.5mm mechanical pencil for constant line width. See our mechanical pencils guide.
• A Hauser Dust Free Eraser and a precision Tombow MONO Zero eraser for small corrections.

Prices change, so see each product page for today’s price. Browse all crafting materials and mechanical pencils.

Drawing parallel and right-angle lines

1. Place a ruler firmly along the bottom of your drawing area and hold it still.
2. Rest one edge of a set square on the ruler.
3. Draw a line up the vertical edge of the set square: this line is at a right angle to the ruler.
4. Slide the set square along the ruler and draw again; each new line is parallel to the first.
5. Use the sloping edge of the set square the same way to draw parallel lines at 45°, 30° or 60°.

How to use a compass neatly

1. Fit a sharp pencil or lead so its tip is level with the compass point.
2. Set the radius against a ruler.
3. Press the point gently into the centre mark.
4. Hold the compass by the top handle and turn it in one smooth movement, tilting slightly in the direction of travel.
5. Keep the pressure light and even so the radius doesn’t slip.

Tips for accurate technical drawings

• Tape your paper down square to the edge of the board.
• Draw construction lines very lightly, then go over final lines more firmly.
• Keep pencils sharp; a blunt point makes lines thicker and less accurate.
• Wipe rulers and set squares clean so they don’t smudge graphite across the page.
• Measure twice and mark lightly before drawing long lines.
• Store set squares flat so they don’t warp.

Technical drawing skills also help with art. Our perspective drawing basics guide uses the same tools.

Frequently asked questions

What is the difference between the two set squares?

One has 45° angles, the other has 30° and 60° angles. Together they let you draw most common angles.

Which compass is good for school?

A sturdy compass that holds its radius firmly. A geometry set is handy if you also need rulers for maths.

Can I use a compass for art?

Yes, for mandalas, patterns and perfect circles in designs.

Do you deliver islandwide?

Yes. We deliver across Sri Lanka in 2–5 working days, with cash on delivery, card or bank transfer. You can also visit our shops in Boralesgamuwa and Horana, open every day from 9 AM to 6 PM.

Not sure what to choose? WhatsApp the Haanz team on 0711 515 515 and we’ll help you put together a technical drawing kit.

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