study guide Flashcards
2 decimal places needed the second # preferred to be even
.04 / 2 = .02
2 Dual Dimensioning Techniques (be able to do examples of each)
Position Method mm/in.
Bracket Method in[mm]
2 Decimal Inches advantages over fractional dimensioning
More Accuracy
Easier to Calculate
Still used in two drafting fields
Architectural
Structural
2 ways to dimension
Be able to write down the notes (a.b.c.) of each way
Unidirectional
a. All dimensions and notes lettered horizontal
b. All text and dimensions are read from the bottom of the drawing.
c. Used in the mechanical industries because easier to read
Aligned.
a. All dimension figures aligned with the dimension line.
b. Vertical dimensions are read from right-side of sheet.
c. Try to avoid dimensioning in the “Gray Area”
* 45° left of vertical
* No dimension in this area if possible
* If not, dimension read from left of sheet
o Know what the gray area is (45 degrees left of vertical)
2 ways to dimension angles
Angle and Linear Dimension
Coordinate Method
Which way is more accurate
Coordinate Method
Definition of a Fillet
Interior Radius on a part
Definition of a Round
Exterior Radius on a part _
What is the standard size of fillets and rounds
1/8” , ¼”, 3mm, 6mm
What is a finish mark used for
To indicate an Area that needs to be Machined or Finished
Where is a finish mark located on the drawing
On any edge view of a finished surface
What is a finish allowance?
The extra material that must be provided to be machined off.
What is the normal finish allowance thickness?
1/8”
What is a counterbored hole used for?
To provide a place to recess bolts and screws.
How is a counterbored hole dimensioned?
Note with leader pointing to outer circle - small diameter, then the counter-bore symbol
space counter-bore diameter, depth symbol then the counter-bore depth.
