Traditional drafting equipment Some board drafters preferred a drafting machine instead of a parallel straightedge because the machine could be used effectively without what auxiliary tool?

Introduction / Context:
Before CAD, manual board drafting relied on tools to maintain geometric accuracy. Two common approaches were the parallel straightedge (or drafting board with parallel bar) and the drafting machine (with protractor head and arms).

Given Data / Assumptions:

• A drafting machine locks to precise angles (typically 0°, 30°, 45°, 60°, 90° and continuous settings).
• A parallel straightedge provides only horizontal reference; vertical or angled lines typically require triangles.
• Goal: reduce tool changes and speed up repetitive angled lines.

Concept / Approach:
With a drafting machine, the protractor head and rulers can be set to a desired angle and locked, enabling parallel lines at that angle anywhere on the sheet. This eliminates the need to place and hold triangles against the straightedge for each vertical or angular line.

Step-by-Step Solution:

Verification / Alternative check:
Compare workflow time: drawing vertical lines with a parallel bar requires a 45°/90° triangle; the drafting machine draws verticals directly, saving steps.

Why Other Options Are Wrong:

• Circle templates and lettering guides are unrelated to the function replaced.
• Technical pens are writing instruments, not alignment aids.

Common Pitfalls:
Poorly calibrated drafting machine angles cause accumulated angular errors; periodic calibration is necessary.

Final Answer:
triangles