CNC Blueprint Reading & Technical Drawing Interpretation 2

Question 1

On a technical drawing, what does a hidden line (dashed line) represent?

Accepted Answer

An edge or feature not visible from the current viewing direction

Answer

Hidden lines are dashed and indicate edges or features that exist behind or inside the part as viewed from that projection direction.

Question 2

A GD&T feature control frame reads ⊙ | 0.005 | A | B. What does the ⊙ symbol indicate?

Accepted Answer

Position

Answer

The circle with a cross (⊙) is the GD&T symbol for Position, controlling the location of a feature relative to datums.

Question 3

What is the purpose of a revision block on an engineering drawing?

Accepted Answer

To document changes made to the drawing after initial release

Answer

The revision block tracks all engineering change orders (ECOs), recording the revision letter, description, date, and approver.

Question 4

In third-angle projection (used in the US), where is the right-side view placed relative to the front view?

Accepted Answer

To the right of the front view

Answer

In third-angle projection, the right-side view is placed to the right of the front view, matching the side from which you are looking.

Question 5

A drawing note specifies 'ALL FILLETS AND ROUNDS R.125 UNLESS OTHERWISE SPECIFIED.' What does this mean for a CNC machinist?

Accepted Answer

All unspecified internal corners and external rounded edges are 0.125-inch radius

Answer

This general note sets a default radius for all unspecified internal fillets and external rounds, saving space on the drawing.

(CNC) Computer Numerical Control Machinist Technical Practice Test