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

unless you know what you are seeing.

L. Tatro CHSE 2011

L. Tatro CHSE 2011

#X: This means that this

applies throughout the drawing ___# of times.

This means diameter

This means centerline

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

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

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

8 2O

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

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

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

industry for specific features.

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.

Flange

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

Keyway

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

8

9

1011

12

13