How to Read a Technical Drawing (Even if You’re Not an Engineer)

Technical drawings are the universal language of manufacturing. They communicate how a component should be made, including its dimensions, materials, tolerances, and surface finishes. While engineers are trained to read these drawings fluently, many procurement officers, managers, or clients often need to interpret them to make informed decisions.

Whether you're sourcing machined components or overseeing production, understanding the basics of a technical drawing can help prevent miscommunication, delays, and costly errors.

What is a Technical Drawing?

A technical drawing—also known as an engineering drawing—is a precise, scaled representation of a part or assembly. It provides all the information a machinist or manufacturer needs to produce that part to exact specifications.

Typically, these drawings are created using CAD (Computer-Aided Design) software and follow standardized conventions (such as ISO or ASME).

Key Elements of a Technical Drawing

1. Views (Orthographic Projections)

Most drawings display the part from multiple angles—top, front, side, and sometimes an isometric view. These are called orthographic projections. Each view shows a flat, two-dimensional slice of the object from a specific angle, allowing the viewer to visualize the full shape.

2. Dimensions

These indicate measurements—length, width, height, diameter, hole locations, etc.—usually in millimeters or inches. The dimension lines include arrows and numerical values to eliminate guesswork.

3. Tolerances

Tolerances specify the acceptable range of variation in a dimension (e.g., ±0.05 mm). This is critical in precision manufacturing, where even a minor deviation can affect part fit or performance.

4. Material Specifications

Most drawings will mention the material to be used—such as SS304, Aluminium 6061, or Brass. This helps the supplier choose the correct stock for machining.

5. Surface Finish and Notes

Symbols or annotations may specify surface finishes (e.g., Ra values), heat treatments, or machining processes (e.g., "drill and ream to size"). General notes at the bottom often clarify additional requirements.

Tips for Non-Engineers

• Focus on the title block: This section (usually at the bottom right) includes the part name, drawing number, material, scale, revision number, and often the name of the designer.

• Start with the isometric view: If available, this 3D-like image gives a quick visual idea of what the part looks like before diving into 2D views.

• Look for critical dimensions: Dimensions tied to holes, threads, or external interfaces are typically the most important for assembly or function.

• Pay attention to units: Metric and imperial units are not interchangeable. Double-check whether the drawing uses millimeters or inches.

• Ask questions when in doubt: Manufacturers like PrimaForm are always ready to clarify drawings to ensure alignment and prevent miscommunication.

Final Thoughts

You don’t need to be an engineer to grasp the essentials of a technical drawing. With a bit of familiarity, anyone involved in procurement, planning, or quality assurance can understand what a drawing communicates—and make better decisions because of it.

At PrimaForm, we believe clear communication starts with the drawing. That’s why we work closely with clients at every step to interpret requirements and deliver exactly to spec, no guesswork, no surprises.