Engineer Constructortechnical drawing and design from scratch: a self-study reference

An independent reference for learning technical drawing and design on your own. It is not a forum, an educational institution or a design firm, and it is not connected to the former website on this domain; we do not sell projects or drawings.

Terms

Terms

Technical drawing has its own vocabulary, and at first the same words can sound different in a textbook and in a workshop. Here are the terms you meet from the very first lessons. The definitions are deliberately short: they are meant as a foothold, and you will find the details in the lessons, the methods section and engineering graphics textbooks.

The precise word saves time: a sectional view and a cross-section are not the same thing, and a maker knows it.

— Key idea

How this glossary works: terms are split into three groups: representations, dimensions and accuracy, and documentation. Definitions are given in general terms; where a concept is based on a standard, we say so explicitly.

Views and representations

View
A picture of the visible part of an object facing the observer. Where needed, hidden features are also shown on the view with dashed lines.
Front view
The view that gives the fullest idea of an object's shape and size. Both drawing and reading a drawing start from it.
Sectional view
A picture of an object imagined as cut by a plane, showing both what lies in the cutting plane and what lies behind it.
Cross-section
A picture of only the shape formed in the cutting plane, without anything that lies behind it.
Detail view
An additional enlarged picture of a small part of the object that is hard to make out on the main view.
Axonometric projection
A pictorial three-dimensional representation that shows several sides of an object at once. It helps you understand the shape but usually does not replace views for manufacturing.

Dimensions and accuracy

Dimension line
A line with arrowheads at its ends, with the number written above it. It shows which features the dimension is measured between.
Extension line
A thin line that carries a dimension outside the outline of the picture so that the number does not get in the way of reading the shape.
Overall dimension
The largest size of an object in length, width or height. It tells you how much space the object will take and what blank to make it from.
Scale
The ratio of the size of the picture to the real size of the object. In Russia the standard range of scales is set by GOST 2.302-68; full size is written as 1:1.
Tolerance
The permitted deviation of the actual size from the size on the drawing. No part can be made perfectly exact, and the tolerance says how much inaccuracy is still acceptable.
Surface roughness
A measure of the fine irregularities of a surface after machining. It is shown on a drawing when the part's function depends on how smooth the surface is.

Documentation

ESKD
The Unified System for Design Documentation: a set of GOST series 2 standards that sets the rules for drawings in Russia. Other countries use their own standards, with ISO standards widely used internationally.
Sheet format
The size of a drawing sheet. The main formats under GOST 2.301-68 are A0, A1, A2, A3 and A4, the same as ISO 216; the smallest, A4, measures 210 × 297 mm.
Title block
A box on the sheet with information about the document: the product name, the drawing number, the scale, the material and the signatures of those responsible.
Assembly drawing
A drawing that shows a product made of several parts in its assembled state and how those parts are joined.
Parts list
A list document that shows all the components of an assembly and their quantities.
Design brief
A description of what the future product should be: what it is for, the conditions it works in and the requirements it meets. Every design job starts with one.
  • Lessons

    Six core lessons: lines and lettering, views, sections, dimensions, sheet sizes and scales, and the assembly drawing.

  • Methods

    How a sketch differs from a drawing and a 3D model, how to read a view of a part, what ESKD is, and which myths get in the way of learning.

  • Questions

    Answers about this reference, about technical drawing, and about how student projects and final projects are organised.

Sources

  • GOST 2.301-68, GOST 2.302-68, GOST 2.303-68, GOST 2.307 (Russian ESKD standards)
  • Engineering graphics and technical drawing textbooks

Drawing rules here follow the Russian ESKD standards listed in the sources; everything else is described in general terms based on engineering graphics textbooks. Other countries use their own drawing standards, and ISO standards are widely used internationally. Standards are revised from time to time, so check the current edition and your instructor's requirements before handing in work.