What are engineering symbols?

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What are engineering symbols?

A drawing is a visual representation of an object which can be interpreted by someone else. Engineering drawings are a type of technical drawing, which is used to document the design and manufacturing process. Engineering drawings are also known as technical drawings or mechanical drawings.

In order to create an engineering drawing, symbols and abbreviations are used. These symbols and abbreviations are called engineering drawing abbreviations or engineering symbols. The most common types of engineering symbols include: arrows, circles, lines, shapes, numbers, letters and words.

Engineers use abbreviations and symbols to quickly communicate their ideas to other engineers. These symbols are often used in engineering drawings to shorten the time it takes to draw them.

Engineers use abbreviations and symbols because they are more efficient than writing out the whole word or sentence. Symbols are often used in engineering drawings because they take less time for an engineer to draw than writing out the whole word or sentence.

Engineers use a lot of abbreviations in their drawings. This makes it difficult for the non-engineer to read them. In order to make the drawings more readable, engineers need to be aware of the following abbreviations and their meanings:

AF: Across Flats

ASSY: Assembly

CM: Centimeters

CL: Center line

CHAM: Chamfered

CH HD: Cheese Head

CSK: Countersink

CSK HD: Countersink Head

C’BORE or CBORE: Counterbore

CYL: Cylinder or Cylindrical

DATUM: Datum System

“: Degree (of angle)

DIA: Diameter

DIM: Dimension

DRG: Drawing

ENG: Engine, engineering

EQUI SP: Equally Spaced

EXT: External 

FIG: Figure

FT: Foot

GAL: Gallon

GALV: Galvanized

HRA: Hardness Rockwell A scale

HRB: Hardness Rockwell B scale

HRC: Hardness Rockwell C scale

HRD: Hardness Rockwell D scale

HRE: Hardness Rockwell E scale

HB: Hardness Brinell

HV: Hardness Vickers

HEX: Hexagon

HEX HD: Hexagon head

HYD: Hydraulic

IN: Inch

INSUL: Insulated, insulation

INT: Internal

I/D: Internal diameter

JT: Joint

KG: Kilogram

LH: Left hand

LG: Long

M/C: Machine

MATL: Material

MAX: Maximum

M: Meter

MM: Millimeter

MIN: Minimum, Minute 

NTS: Not to scale

NO.: Number

O/D: Outside diameter

PCD: Pitch circle diameter

QTY: Quantity

LB: Pound

RAD or R: Radius

RPM: Revolutions per minute

RH: Right hand

RD HD: Round head

SCR: Screwed

SK: Sketch

SPEC: Specification

SPH: Spherical

SQ: Square

STD: Standard

SWG: Standard wire gauge

THD: Thread

TPI: Thread per inch

VOL: Volume

WT: Weight

AC: Across corners

ALY: Aluminum

ANN: Anneal

AQL: Acceptable quality level

AR: As required

AVG: Average

BASIC or BSC: Basic dimension

BC or B.C.: Bolt circle

BHC: Bolt hole circle

BRZ: Bronze

CAD: Computer-aided design

CERT: Certification

CI: Cast iron

CNC: Computer Numerical Control

CRES: Corrosion-resistant

DIM: Dimension

ED: Edge distance

IAW: In accordance with

LMC: Least material condition

MBP: Measurement between pins

MBW: Measurement between wires

MFD: Manufactured

MFG: Manufacturing

MFR: Manufacturer

MMC: Maximum material condition

OAL: Overall length

PC: Piece

PD: Pitch diameter

PL: Parts list

PMI: Product and manufacturing information

REF: Reference

RZ: Roughness, mean depth

SFACE: Spotface

SN: Serial number

STD: Standard

UNC: Unified National Coarse

UNS: Unified National Special

YS: Yield Strength

Engineering Drawing Symbols

The common Engineering Drawing Symbols are used for various purposes. They are used to convey information about the drawing, such as the type of drawing, the size and scale of the drawing, and other relevant information. The following is a list of symbols that are commonly found in engineering drawings:

Basic types of symbols used in engineering drawings are countersink, counterbore, spotface, depth, radius, and diameter. Here are more commonly used engineering drawing symbols and design elements as below. 

engineering drawing symbols
engineering drawing symbols
Author: Mose Li

Author: Mose Li

Director of Project Engineering at 3Q Machining

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