Engineering Drawing Abbreviations and Symbols Guide- Huili (2024)

CNC design is an integral part of CAD/CAM technology. You use these drawings for the development and production of a product.

However, engineering drawings are complex. They are full of symbols, abbreviations, and strange phrases that you may not be able to decipher. This is where the meanings behind these various pieces come in handy!

While you may understand the basic terms such as KG and CM, it becomes more difficult when you come across terms such as CYL and EQUI SP. If you have found it tough to interpret CNC designs, we’ve got your back!

We have prepared an extensive list of engineering drawings abbreviations and symbols for you to reference. Read on.

Benefits of Using Abbreviations and Symbols in Engineering Drawings

The design of an engineering drawing is critical. The abbreviations and symbols used must be concise. They should provide all the necessary information to produce a CNC milling part without a hassle.

Because there is no room on your image for text, symbols & abbreviations are relatively less overwhelming. When well used, they result in clean and uncluttered images, allowing the viewer to grasp all important aspects of your design.

To further aid comprehension of what is on paper, abbreviations and symbols must be accurate. One typo can lead to serious consequences like making something too heavy. So make sure you understand them well!

Are Engineering Drawing Abbreviations and Symbols Standardized?

As with other engineering terms, abbreviations and symbols are subject to standardization. In the United States, the majority of these terms follow Norms ANSI or ASA. ASME handles some specific ones related to mechanical engineering.

Other international engineering standards include ISO, AS (Australia), AFNOR (France), USA (AISI, ASTM, AMS, ANSI, and SAE), AFNOR (France), UNI (Italy), KS (Korea), Germany (DIN and WR), JIS (Japan), SS (Sweden), and BS (UK). You should note that an abbreviation can have different meanings in different categories.

In addition to these worldwide standards, each design firm has its own set of requirements. As such, you should check what your company’s preferred abbreviations and symbols are.

Common Engineering Drawing Abbreviations

There are numerous abbreviations and symbols in various engineering drawing categories. You can use this guide as a reference to help you decipher what is written on your engineering drawing. Also check GD & T symbols and terms here.

Here’s the complete list of abbreviations and symbols in alphabetical order for easy reference:

AF: Across Flats HEX HD: Hexagon head MM: Millimeter
Ą°: Degree (of angle) HEX: Hexagon NO.: Number
ASSY: Assembly HRA: Hardness Rockwell A scale NTS: Not to scale
CĄŻBORE or CBORE: Counterbore HRB: Hardness Rockwell B scale O/D: Outside diameter
CH HD: Cheese Head HRC: Hardness Rockwell C scale PCD: Pitch circle diameter
CHAM: Chamfered HRD: Hardness Rockwell D scale QTY: Quantity
CL: Center line HRE: Hardness Rockwell E scale RAD or R: Radius
CM: Centimeters HV: Hardness Vickers RD HD: Round head
CSK HD: Countersink Head HYD: Hydraulic RH: Right hand
CSK: Countersink I/D: Internal diameter RPM: Revolutions per minute
CYL: Cylinder or Cylindrical IN: Inch SCR: Screwed
DATUM: Datum System INSUL: Insulated, insulation SK: Sketch
DIA: Diameter INT: Internal SPEC: Specification
DIM: Dimension JT: Joint SPH: Spherical
DRG: Drawing KG: Kilogram SQ: Square
ENG: Engine, engineering LB: Pound STD: Standard
EQUI SP: Equally Spaced LG: Long SWG: Standard wire gauge
EXT: External? LH: Left hand THD: Thread
FIG: Figure M/C: Machine TPI: Thread per inch
FT: Foot M: Meter VOL: Volume
GAL: Gallon MATL: Material WT: Weight
GALV: Galvanized MAX: Maximum
HB: Hardness Brinell MIN: Minimum, Minute?

More engineering drawing abbreviations can be used in CNC manufacturing, including:

AC: Across corners CNC: Computer Numerical Control PC: Piece
ALY: Aluminum CRES: Corrosion-resistant PD: Pitch diameter
ANN: Anneal DIM: Dimension PL: Parts list
AQL: Acceptable quality level ED: Edge distance PMI: Product and manufacturing information
AR: As required IAW: In accordance with REF: Reference
AVG: Average LMC: Least material condition RZ: Roughness, mean depth
BASIC or BSC: Basic dimension MBP: Measurement between pins SFACE: Spotface
BC or B.C.: Bolt circle MBW: Measurement between wires SN: Serial number
BHC: Bolt hole circle MFD: Manufactured STD: Standard
BRZ: Bronze MFG: Manufacturing UNC: Unified National Coarse
CAD: Computer-aided design MFR: Manufacturer UNS: Unified National Special
CERT: Certification MMC: Maximum material condition YS: Yield Strength
CI: Cast iron OAL: Overall length

Engineering Drawing Symbols

Besides the abbreviations, CNC and engineering drawings also feature symbols. They describe various components and how each part should be made.

Engineering drawing symbols represent views of several geometry types such as surfaces (flat, cylindrical, spherical & toroidal), lines (linear, reference & centerlines), points (center & intersection), and also some standard views for orthographic projections, section view, and auxiliary views.

In the picture below, you can see a list of the most used engineering drawing symbols:

Engineering Drawing Abbreviations and Symbols Guide- Huili (1)

Additionally, different software packages have different sets of symbols available to create a drawing. At times, you may modify an existing one or create your symbol.However, it’s best to stick with the standard symbols, that way you will avoid interoperability issues.

Engineering Drawing Abbreviations and Symbols Guide- Huili (2024)
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