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
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