Features… Learning to read the information

Every drawing should include all the information… however, it is not always clear

unless you know what you are seeing.

L. Tatro CHSE 2011

Students should be able to… Understand the different meanings of

commonly used symbols used in drafting. Relate terms to the appropriate features. Visually identify different features and

understand how they are displayed in drafting.

Objectives

Reading the numbers… Understanding the symbols…

L. Tatro CHSE 2011

Often times symbols are used to help explain what we are seeing in the drawings. Universal symbols are used so every person reading the drawings can understand them…

If they know the meaning of each symbol used.

Symbols…#X: This means that this applies

throughout the drawing ___# of times.

n This means diameter

q This means centerline

v This means Counterbore (a square cut oversized hole symmetrically around a smaller through hole

x This means depth. This will be given when a hole, or counterbore does not go through the entire part.

w This means countersink. When a hole has an interior chamfer this symbol is used.

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Along with a countersink symbol, a degree value is given for the tapered angle.

17.08 When seeing a set of numbers 17.25 stacked, this is used to give a acceptable range (tolerance).

L. Tatro CHSE 2011

Continued R This means radius

TYP This means typical and is used when a drawing has a situation that repeats itself and is constant.

EQL SP Used when the distance between hole or features have a repeating value. Typically used in polar dimensioning .

BC means bolt circle and is used when a circular centerline is used to make the center locations of a bolt pattern.

L. Tatro CHSE 2011

Understanding the terms..

This segment will help you identify and understand many of the terms used in the

drafting/machining industry for specific features.

From Page 134 from your text

Fillet: A rounded interior blend between surfaces.

Round: A rounded exterior blend between surfaces.

Counterbore: A cylindrical recess around a hole, usually to receive a bolt head or nut.

Countersink: A conical shaped recess around a hole, usually to receive a tapered screw head.

Spotface: A shallow recess like a counterbore, used to provide a good bearing surface for a fastener.

Boss: A short raised protrusion above the surface of a part, often used to provide a strong flat bearing surface. Bos

s

Lug: A flat or round tab protruding from a surface usually to provide a method for attachment.

Flange: A flattened collar or rim around a cylindrical part to allow for attachment.

Chamfer: An angled surface, used on cylinders to make them easier to start.Flan

ge

Lug

Neck: A small groove cut around the diameter of a cylinder or hub to receive a key, used to attach hubs, gears, and other parts to a cylinder so they won’t turn on it

Keyway : A shaped depression cut along the axis of a cylinder to receive a key (When mating two parts to prevent rotation).

Neck

Keywayalouline.info

Knurl: A pattern form on a surface to provide for better gripping or more surface area for attachment, often used on knobs and tool handles.

Bushing: A hollow cylinder that is often used as a protective sleeve or guide, or as a bearing.

Rib: Like a boss, a rib is used internally to add strength to, or between features.

RIB

Self Quiz…. Left click to see the feature name in order 1

2

3

4

5

6

7

89

1011

1213

Understanding Lines and their meaning

CUTTING PLANE LINEMED-DRK AND THICK

SECTION/HATCH LINESMED-THIN @45 DEGREES AND EVENLY SPACED

BORDER LINEDRK AND THICKOBJECT OR VISIBLE

DRK AND THICK

CENTER MARKMED AND THIN

CENTER LINEMED & THIN

TITLE BLK/BORDER LINEDRK AND THICK

EXTENSIONMED AND THINDIMENSION LINE

MED & THIN

CONSTRUCTION LINE LIGHT AND THIN