Detailed Drawings Flashcards
Drawing must include
Dimensions, units and scale Projection (first or third) Important details and sectioned views Who made the drawing and when Tolerances Material Isometric view
Dimension lines
Must include: Gap between object and extension line Extension line Feature size Arrowheads Dimension line (between extension lines) Neatly stacked
Holes
Must have centremarks/centre lines
Curls with dash through symbol is the diameter
Mn is also diameter but specifies thread size by standard metrics thread system
Square hole
Square symbol
Counterbore hole
Square u symbol, and is when the screw is sunk into the material so the top is the same as the surface of the material
Countersunk
V symbol
Same as counterbore, but there is an angle between screw head and screw body
Threads
Represented by dashed lines in all views
Pitch
The distance between the threads
Nominal diameter
Diameter of nail body
PCD
Pitch circle diameter
The diameter of a bunch of screws on the same circular line
Tolerance
The variation in size that is tolerated
Format
+….
-….
Fit
The result of a certain tolerance
Clearance
The hole is larger than the shaft enabling the shaft to slide or rotate
Location/transition
The hole is fractionally smaller than the shaft so small force is required to assemble
Interference
The hole is smaller than the shaft to lots of force and temperature manipulation is required to assemble
