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3D Printer: A machine allowing the creation of a physical object from a digital model.

A

Allowance: The minimum clearance (or maximum interference) of two parts.

Alloy: A mixture of two or more elements, one or more being metallic, melted together to create a type of metal.

Angular Dimension: A dimension used to measure an angle in decimal degrees or degrees, minutes, and seconds.

Anneal: The process of heating iron-based metal to a specific temperature then slowly cooling to reduce hardness and remove stress.

Assembly: The process of joining individual parts to create a complete product.

Assembly Drawing: A print or drawing showing how individual parts come together to form a complete product.

Annotation: Textual information on a blueprint, such as notes, dimensions, or symbols.

Auxiliary View: A secondary view of an object showing a specific detail not clearly visible in the main view.

Axis: A central line that a part or parts are symmetrical around and may rotate around.

B

Blind Hole: A hole that does not pass through the material.

Bill of Materials (B.O.M): A list of all components required to assemble a product, including quantities and specifications.

Bolt circle: Circular centerline in which two or more holes are located.

Bore: Enlarging a hole to an accurate size.

Boss: A circular portion raised from a surface.

Burr: A sharp or jagged edge created by many metal cutting and forming processes.

C

Casting: A metal object created by molten metal poured or injected in a mold.

Chamfer: A beveled edge on a corner, often specified by angle or dimensions.

Chamfer Dimension: Specifies the angle and/or size of a chamfered edge.

Clearance: The space between two mating parts.

Clearance Hole: A hole with a diameter larger than the mating part’s diameter, allowing for clearance.

Computer-aided drafting (CAD): A software-based process that allows users to create and analyze designs before committing to production.

Core: A part of a mold used to create interior shapes of the casting.

Contour: The overall outline or shape of an object.

Counterbore: A cylindrical enlargement at the end of a hole for a fastener head to sit flush.

Countersink: A conical depression at the end of a hole for a screw head to sit below the surface.

CNC (Computer Numerical Control) machine: A machine using pre-programmed software to control the movement of tools and machinery in manufacturing.

D

Datum: A theoretical reference surface used for dimensioning and tolerancing.

Datum Plane: A theoretically flat surface used as a reference for dimensioning and tolerancing.

Detail Drawing: A print or drawing focusing on a specific part, providing all the details and information necessary to manufacture the part.

Detail Specification: Additional information specific to a particular part beyond the general blueprint.

Dimension: The numerical measurement of an object’s features, such as length, width, or height.

Dimension Line: A thin line with arrowheads at both ends indicating the measurement location.

Dimensioning System: The method used to specify dimensions on a blueprint (e.g., parallel, coordinate).

Draft Angle: A slight taper on the sides of a molded part to facilitate removal from the mold.

E

Extension Line: A thin line extending beyond the object to accommodate dimension lines and arrowheads.

Extrusion: An object created by pushing material through dies to form the desired shape.

F

Fillet: A concave curved edge where two surfaces meet creating an internal corner, often specified by radius.

Finish: The surface texture or treatment applied to a component.

Finish Symbol: A symbol on a blueprint indicating the desired surface finish.

First-angle projection: a method of creating orthographic drawings where the views are projected onto planes behind the object.

Fit: The relationship between mating parts, such as tight fit, clearance fit, or interference fit.

Fold Line: A line on a blueprint indicating where sheet metal should be folded, also called bend lines.

G

General Tolerance: A tolerance applied to all dimensions on a blueprint unless otherwise specified.

Geometric Dimensioning and Tolerancing (GD&T): A system for specifying exact geometry and allowable variations on blueprints.

Geometric Tolerance: A tolerance applied to the form, orientation, profile, location, or run-out of a feature.

Gusset: An angled piece placed between two joined pieces to provide additional strength.

H

Hidden Line: A dashed line representing features not visible from the current viewing angle.

Hole: A circular opening through a material.

Hole Callout: Specifies the size, depth, and other relevant information for a hole.

I

Inspection: The process of verifying that a manufactured part meets blueprint specifications.

Inspection Report: A document where inspection results are recorded.

Interference Fit: A tight fit where the mating parts require force to assemble.

Isometric Drawing: A three-dimensional drawing showing the object at a specific angle, allowing the viewer to see the front, top, and side of the object simultaneously.

L

Landing: A machined surface designed to provide a bearing surface for another part.

Least Material Condition (LMC): When a feature contains the minimum amount of material allowed by the feature tolerance.

Leader Line: A thin line with an arrowhead pointing to a specific feature and connecting to a note or symbol.

Limits: The maximum and minimum allowable size of a feature.

Line Type: The style of line used on a blueprint to convey different information. (e.g., solid, dashed, dotted).

M

Machining Symbol: A symbol on a blueprint specifying the machining process required for a feature.

Machining Tolerance: A tolerance applied to a feature created by a machining process.

Material: The substance used to manufacture a component.

Material List: A list of materials required for a project, including types, quantities, and specifications.

Maximum Material Condition (MMC): When a feature contains the maximum amount of material allowed by the feature tolerance.

Metric System: A system of measurement based on meters and grams.

Metric Thread: A screw thread with dimensions specified in millimeters.

Mold Line: A line on a blueprint indicating the parting line of a mold used to create a part.

Multi-view drawing: a two-dimensional representation of a three-dimensional object using multiple views to convey the shape and size of the object.

N

Nominal Size: The basic size of a component, not necessarily the exact manufactured size.

O

Oblique drawing: a method of drawing that shows three sides of an object by using lines of sight at an angle to the plane of projection.

Offset: The displacement of a feature from a reference point.

Orthographic Projection: A method of drawing that creates multiple two-dimensional views of an object on a flat surface.

Orthographic Projection Views: Standard views (front, top, side) of an object created using orthographic projection.

P

Pattern: A template used to create repetitive features on a part.

Pattern Development: The process of creating a flat pattern for a three-dimensional sheet metal part.

Perspective Drawing: A three-dimensional drawing showing the object as it appears to the eye.

Pictorial drawing: a three-dimensional representation of an object.

Pilot Hole: A small hole drilled before creating a larger hole, which allows for better accuracy and alignment.

Pin: A cylindrical rod used to locate or secure parts.

Principal view: One of the six views of an object that are used in multi-view orthographic drawings.

Print reading: The ability to read text and images to understand engineering drawings.

Projection: The representation of a three-dimensional object on a two-dimensional plane.

Projected View: A view of an object created by projecting its features onto a plane.

R

Radius: The distance from the center of a circle or arc to a point on its circumference.

Reference Dimension: A dimension that does not carry any tolerance.

Regardless of Feature Size (RFS): Where a tolerance zone is not affected by the size of the feature.

Revision Cloud: A wavy circle on a blueprint highlighting changes made to the design.

S

Scale: The ratio between the actual size of an object and its representation on a blueprint.

Screw: A threaded fastener that screws into a tapped hole.

Screw Thread Designation: Specifies the thread type, diameter, and pitch.

Section Line: Thin parallel lines at regular intervals indicating material that has been cut through by the cutting-plane line, often placed at a 45 degree angle.

Sectional View Types: Different types of sectional views (full, half, offset) depending on the information needed.

Section View: A view of an object showing its internal details by cutting through it along an imaginary plane.

Sheet Metal: Thin flat metal sections that are less than 3/16″ (5MM) thick.

Sheet Metal Gage: A system for specifying the thickness of sheet metal.

Shop Drawing: A blueprint used on the shop floor to guide manufacturing processes.

Shop Note: Additional instructions or clarifications added to a blueprint for manufacturing.

Slot: A long, narrow opening in a part.

Slot Dimension: Specifies the length, width, depth, and location of a slot.

Spotface (SF): To flatten a rough surface around a hole for a bolt head to contact.

Standard: Established specifications for materials, processes, or components.

Standard Hole Sizes: Standardized sizes for commonly used drilled holes.

Surface Finish: The smoothness or roughness of a machined surface.

Surface Texture Symbol: A symbol on a blueprint specifying the desired surface roughness.

Supplement: An additional sheet attached to a blueprint providing further details.

Symbol: A graphical representation on a blueprint conveying specific information (e.g., weld symbol, surface texture symbol).

Symmetrical: Equal halves, usually split with a centerline.

T

Tolerance: The allowable deviation from a specified dimension.

Tolerance Stack-Up: The cumulative effect of multiple tolerances on a final dimension.

Thread: A helical groove on a cylindrical surface used to create a fastening mechanism.

Three-dimensional (3D) model: A digital representation of an object that is created using computer software.

Third-angle projection: a method for creating two-dimensional drawings of three-dimensional objects projecting each view onto the plane closest to it.

Title Block: A section on a blueprint containing information like title, scale, revision number, and creator.

U

Uniform Tolerance: A single tolerance applied to all dimensions of a specific type (e.g., all hole diameters).

V

Visible Object Line: The thickest line and defines the visible edges and outlines of the object being depicted.

W

Weld Symbol: A symbol on a blueprint specifying the type and details of a weld.

Weld Zone: The area where two pieces of metal are joined by welding.