Many buyers and engineers struggle when reading technical drawings — especially when working with international suppliers.
Understanding a drawing correctly ensures that your product is manufactured to the right specifications, with fewer errors and faster lead times.
This guide explains the most important elements of a technical drawing in a simple, practical way.
The title block is usually located at the bottom-right corner.
It contains key information such as:
This section tells the manufacturer exactly what they are making and which version is correct.
Dimensions show the size of every feature on the part.
They must be clear and readable.
There are two types:
If a dimension is missing or unclear, it can lead to machining errors or delays.
Always check that all functional features are dimensioned properly.
Tolerances specify how much variation is allowed from the ideal size.
This directly impacts cost, machining time, and quality.
Examples:
Unnecessary tight tolerances increase cost and reject rates.
Define tolerances only where needed.
Technical drawings typically include multiple views so the manufacturer can see the part from different angles:
Each view provides different information.
Together, they form a complete understanding of the part geometry.
Holes are often shown with specific symbols and notes.
A proper callout includes:
Example: M4 × 0.7 – 8 mm depth
This ensures the hole is machined exactly for the correct screw.
Surface finishes affect both appearance and performance.
Common finishes include:
If a finish is missing from the drawing, manufacturers may not know how the final part should look.
Many drawings include general notes to clarify machining requirements:
These notes help ensure the final product meets functional and aesthetic expectations.
Drawings often change during development.
The revision column shows what was updated and when.
Manufacturers must always follow the latest revision to avoid producing outdated parts.
Learning how to read a technical drawing is essential for efficient communication with CNC manufacturers.
A clear understanding of dimensions, tolerances, views, and finishes helps prevent mistakes, reduce costs, and ensure the final product meets your expectations.
If you struggle with drawings, working closely with your supplier can save time and production cost.