Have you ever looked at a technical drawing and seen abbreviations like DRG, CSK, SK, or SQ and wondered what they mean? In the world of CNC machining, mechanical design, and engineering drawings, these shorthand notations are essential for conveying complex information clearly and efficiently. This article breaks down the most common abbreviations and symbols found on engineering and technical drawings, explains why they are used, and offers a handy reference table for quick lookup.
Why Use Abbreviations and Symbols in Engineering Drawings?
Technical drawings are critical blueprints used by manufacturers, machinists, and engineers to fabricate parts. But space on these drawings is limited. Instead of writing out full words or sentences, engineers use abbreviations and symbols that are universally understood across industries.
Here’s why they matter:
- Save space and make drawings neater.
- Standardized across countries and industries.
- Speed up communication between design and production teams.
- Help avoid errors by using clearly defined terms.
Different international standards regulate these notations, including ISO (International), ANSI (USA), JIS (Japan), DIN (Germany), and others.
Key Engineering Drawing Abbreviations & Their Meanings
Here is a spreadsheet-style table showing some of the most common abbreviations and symbols used in engineering drawings:
| Abbreviation | Meaning | Use |
|---|---|---|
| DRG | Drawing | Refers to the complete design sheet |
| CSK | Countersink | For conical holes for screws |
| CBORE | Counterbore | Flat-bottomed hole enlargement |
| SK | Sketch | Freehand drawing or simplified view |
| SQ | Square | Indicates a square shape or feature |
| EQUI SP | Equally Spaced | Used in bolt holes or slots |
| CYL | Cylinder / Cylindrical | Refers to round features or geometry |
| DIA | Diameter | Circular measurements |
| DIM | Dimension | Specifies size |
| MATL | Material | Indicates required material |
| REF | Reference | Non-critical dimension or note |
| THD | Thread | Indicates a screw thread feature |
| CL | Center Line | Symmetry or reference axis |
| NTS | Not to Scale | Visual only, not used for measurement |
| MAX / MIN | Maximum / Minimum | Limits on size or range |
| LH / RH | Left Hand / Right Hand | Thread direction or handedness |
| PCD | Pitch Circle Diameter | Bolt hole pattern |
| RPM | Revolutions per Minute | Rotational speed |
| MFG | Manufacturing | Refers to production processes |
Popular Abbreviations Explained
Here are the meanings behind your keyword-based abbreviations:
- DRG (Drawing): The full design blueprint of a part or assembly.
- CSK (Countersink): A conical hole for flat-head screws. Often indicated with diameter and angle (e.g., CSK Ø10 × 90°).
- SK (Sketch): A simplified or freehand view, often used in conceptual stages.
- SQ (Square): Indicates a square-shaped feature or measurement (e.g., SQ 10 means a 10mm square).
- CYL (Cylinder/Cylindrical): Refers to circular components like shafts or bores.
- EQUI SP (Equally Spaced): Holes or features spaced at equal distances—common in flanges or bolt hole circles.
Engineering Drawing Symbols: More Than Just Abbreviations
In addition to abbreviations, engineering drawings include standardized symbols to indicate:
- Weld types
- Surface finishes
- Tolerances
- Geometric Dimensioning & Tolerancing (GD&T)
For example:
- A countersink symbol is typically a “V” shape.
- Surface finish may be shown as a checkmark-like symbol with roughness values.
- GD&T symbols like ⌀ (Diameter) or ⌖ (Position) define part precision.
Whether you’re designing a precision-machined part or reviewing a supplier’s drawing, understanding engineering drawing abbreviations and symbols is critical for accurate communication and error-free manufacturing. Next time you see abbreviations like DRG, CSK, EQUI SP, or CYL, you’ll know exactly what they mean—and why they matter.