Every drawing should include all the information… however, it is not always clear unless you know what you are seeing. L. Tatro CHSE 2011

 #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.  8 2 O Along with a countersink symbol, a degree value is given for the tapered angle.  When seeing a set of numbers 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. Boss

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. Flang e Lu g

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). Nec k 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