D3 - MASTER THE DAY

What is the BIS standard number for lettering in technical drawings?

• IS 962-1989

• IS 800-2007

• IS 11669-1986

• IS 456-2000

Answer explanation

What’s the difference?

• IS 9609 (Part 1)
  → This is the dedicated and specific standard for lettering in all technical drawings, including engineering and architectural ones. It defines sizes, stroke thickness, spacing, and orientation of letters.

• IS 962 – 1989
  → This is a broader standard related to architectural/building drawings. It includes some guidelines on lettering, but it's not the primary lettering standard. Instead, it often refers to IS 9609 for lettering rules.

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📌 Conclusion:

• Use IS 9609 (Part 1): 1991 when referring specifically to lettering.

• IS 962:1989 is valid but more general — it includes lettering among other drawing conventions.

If you're preparing for exams like Kerala PSC (Civil), it's safest to quote IS 9609 (Part 1) – 1991 for lettering standards.

Letters are designated primarily by their:

• Width

• Area

• Height

• Stroke thickness

The height to width ratio for lettering is generally taken as:

• 5:6

• 6:5

• 1:1

• 3:2

Horizontal lines for lettering are drawn: a) Right to left b) Left to right c) Bottom to top d) At random.

• Right to left

• Left to right

• Bottom to top

• At random

Vertical lines for lettering are drawn: a) Bottom to top b) Diagonally c) Top to bottom d) Randomly.

• Bottom to top

• Diagonally

• Top to bottom

• Randomly

Answer explanation

In engineering lettering, especially when using pencils or pens for manual drawing, the direction of strokes is standardized to:

• Ensure uniformity

• Maintain control over the stroke

• Reduce smudging and strain

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✍️ Why "Top to Bottom"?

• Vertical lines in letters (like in E, F, H, I, L, T, etc.) are always drawn from the top towards the bottom.

• This stroke direction:

  • Allows better visibility of what is being drawn.

  • Helps in maintaining line thickness and consistency.

  • Reduces the chances of smudging, especially when using ink or soft pencil.

  • Is ergonomically more natural for right-handed and left-handed people alike.

The minimum recommended height of letters used for dimensioning is:

• 2 mm

• 5 mm

• 3 mm

• 6 mm

Which lettering style is drawn straight up at 90° to the baseline?

• Inclined

• Italic

• Vertical

• Roman

The angle of inclined lettering to the vertical is:

• 45°

• 30°

• 15°

• 75°

Which letter type is thicker and used for main titles in ink drawings?

• Gothic

• Roman

• Italic

• Script

Minimum height of letters in Gothic style should be:

• 6 mm

• 10 mm

• 15 mm

• 20 mm