Mechanical Drawing Symbols

The vector stencils library "Dimensioning and tolerancing" contains 45 symbols of geometric dimensions and mechanical tolerances, geometric symbols, callouts, and text boxes and inserts.
Use these geometric dimensioning and tolerancing (GD&T) shapes to create annotated mechanical drawings.
"Geometric dimensioning and tolerancing (GD&T) is a system for defining and communicating engineering tolerances. It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that explicitly describes nominal geometry and its allowable variation. It tells the manufacturing staff and machines what degree of accuracy and precision is needed on each controlled feature of the part. GD&T is used to define the nominal (theoretically perfect) geometry of parts and assemblies, to define the allowable variation in form and possible size of individual features, and to define the allowable variation between features." [Geometric dimensioning and tolerancing. Wikipedia]
The shapes example "Design elements - Dimensioning and tolerancing" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Mechanical Engineering solution from the ConceptDraw Solution Park.

The vector stencils library "Terminals and connectors" contains 43 element symbols of terminals, connectors, plugs, polarized connectors, jacks, coaxial cables, and conductors.
Use it for drawing the wiring diagrams, electrical layouts, electronic schematics, and circuit diagrams.
"An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. Connectors consist of plugs (male-ended) and jacks (female-ended). The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or devices. An adapter can be used to effectively bring together dissimilar connectors.
There are hundreds of types of electrical connectors. Connectors may join two lengths of flexible copper wire or cable, or connect a wire or cable or optical interface to an electrical terminal.
In computing, an electrical connector can also be known as a physical interface... Cable glands, known as cable connectors in the US, connect wires to devices mechanically rather than electrically and are distinct from quick-disconnects performing the latter." [Electrical connector. Wikipedia]
"A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener. In network analysis, terminal means a point at which connections can be made to a network in theory and does not necessarily refer to any real physical object. In this context, especially in older documents, it is sometimes called a "pole".
The connection may be temporary, as seen in portable equipment, may require a tool for assembly and removal, or may be a permanent electrical joint between two wires or devices.
All electric cell have two terminals. The first is the positive terminal and the second is the negative terminal. The positive terminal looks like a metal cap and the negative terminal looks like a metal disc. The current flows from the positive terminal, and out through the negative terminal, replicative of current flow (positive (+) to negative (-) flow)." [Terminal (electronics). Wikipedia]
The shapes example "Design elements - Terminals and connectors" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the Electrical Engineering solution from the Engineering area of ConceptDraw Solution Park.

This engineering drawing present weld type symbols and fillet weld symbols.
The weld type symbol is typically placed above or below the center of the reference line, depending on which side of the joint it's on. The symbol is interpreted as a simplified cross-section of the weld.
"Fillet welding refers to the process of joining two pieces of metal together whether they be perpendicular or at an angle. These welds are commonly referred to as Tee joints which are two pieces of metal perpendicular to each other or Lap joints which are two pieces of metal that overlap and are welded at the edges. The weld is aesthetically triangular in shape and may have a concave, flat or convex surface depending on the welder’s technique. Welders use fillet welds when connecting flanges to pipes, welding cross sections of infrastructure, and when fastening metal by bolts isn't strong enough." [Fillet weld. Wikipedia]
The engineering drawing example Welding symbols is included in the Mechanical Engineering solution from Engineering area of ConceptDraw Solution Park.