Drawings Flashcards
Define Oblique, Axonometric and Isometric views
Oblique is when there is one ‘flat’ face and the others are angled. Axonometric is when there is no ‘flat’ face and all are angled. Isometric is a specific type of axonometric view at 30 degrees from the horizon line
What is zoning in a drawing
A coordinate system usually using A, B, C … and 1, 2, 3 … to locate areas on a drawing
Explain the difference between third and first angle projection
Third angle is how you would view an object’s views. First angle is if you were the object and rolled the cube faces onto the page
Explain the difference between continuous and baseline dimensioning
Baseline: a datum is selected as an origin and all measurements are based on it. Easier for machinists to read since they don’t have to calculate and less tolerancing errors in manufacturing.
Continuous: dimensions for features adjacent to each other. More compact and highlights the importance of certain features on a part.
What is an orthographic projection
The projections of the ‘flat’ views of an object (i.e. front, back, top, bottom etc.)
What is an auxiliary view
An orthographic projection that gives more details standard views cannot. A common example is to use an auxiliary view on a sloped face to show a hole (in standard view, it’d look like an ellipse)
Why use fillets and chamfers
Fillets reduce sharp corners, increase cross section of part and can save machining costs (no need to swap bit if inner cut feature has rounded edges)
What thicknesses should object, hidden, center, dimension, section, hatching, break and phantom lines be
Object: thick
Hidden: medium
Center: thin
Dimension: thin
Section: very thick
Hatching: thin
Break: thick (same as object)
Phantom: thin
What does TYP mean on a drawing
TYP means typical, which means the same feature will have the same dimensions (e.g. “R0.5 TYP” for all holes on a part)
What is a leader line
A line with an arrowhead that points to a specific feature and has text at the tail (usually to indicate radii for holes and rounds)
What’s the difference between a fillet and an arc
A fillet typically have a radius < 1” while arcs have larger radii
