READOS / Engineering / KEVOS® original book
Drawings That Make Parts
Mechanical engineering drawing practice to AS 1100, from sheet and line to tolerance, surface texture and release
Make and read mechanical drawings that suppliers can quote, make and inspect from: sheets, lines, views, sections, dimensions, tolerances, texture and release.
Start readingAbout this book
A mechanical drawing is an instruction to strangers. The machinist, the inspector, the buyer and the supplier’s estimator will read it without you in the room, often years after it was drawn, sometimes after it has been printed at the wrong size or copied from a copy. Everything they need must be on the sheet, and every mark must mean one thing. The conventions in the Australian drawing standards exist to make that possible.
This book works through those conventions in the order a drawing is built: sheet and title block, lines and lettering, views and sections, dimensions, tolerances, surface texture, conventional representation of standard features, and the final check before release. It is written for people who make drawings and for people who must act on them. It assumes you can read a simple orthographic drawing and do basic arithmetic. It does not teach a CAD package; READOS’s CAD drafting collection covers software practice, and this book explains what the resulting sheet must say.
The running case
Every chapter follows one fictional part. This is an illustration. A small engineering business designs a bearing housing for a centrifugal pump. The housing is machined from a grey iron casting. It has a flange 140 mm in diameter and 12 mm thick, drilled with four 9 mm holes on a 115 mm pitch circle; a body 95 mm in diameter; a locating spigot 100 mm in diameter projecting 5 mm from the flange face; and a bearing bore 62 mm in diameter to take a deep-groove ball bearing. Four M6 tapped holes on a 78 mm pitch circle in the rear face hold an end cap with a lip seal, and an M8 × 1 lubrication hole enters the body at an angle. The overall length is 77 mm.
The housing is drawn on an A3 sheet at full size. Each chapter adds to the drawing, and most chapters include a mistake that a real drawing office or supplier could plausibly make, how it was found and how it was corrected. The part, the business and the mistakes are invented; none describes KEVOS® work or a real supplier.
Source limits and professional responsibility
The conventions in this book come from three supplied Australian Standards: AS 1100.101-1992 on general principles, AS 1100.201-1992 on mechanical engineering drawing, both reconfirmed in 2014, and AS ISO 128.24-2005 on lines for mechanical drawings. Values are cited with their clause, but the standards’ tables and figures are not reproduced. Buy the standards your work calls up from Standards Australia, and check their current status: when this book was written, the Standards Australia store listed AS 1100.101 as pending revision.
Practice has moved on in places. Surface texture indication in particular follows later ISO standards on many overseas drawings, and Chapter 8 explains how to handle the difference. Where a contract or customer specifies a different standard, that standard governs. Tolerances, fits and surface finishes for real parts depend on function and on manufacturers’ data; the values in the running case illustrate how to present requirements, not what they should be.
Who this book is for
Designers, drafters, machinists, inspectors and buyers who prepare, check or work from mechanical engineering drawings and want each convention on the sheet to mean one thing.
What you will learn
- Choose a sheet size, scale, line group and lettering height that survive printing and reduction.
- Select views and sections in third-angle projection and mark the projection method correctly.
- Dimension a part functionally, without redundant or double-toleranced dimensions.
- Apply general tolerances, explicit limits and surface texture symbols that a supplier can inspect.
- Represent threads, centre holes, seals and other features by convention, and check a drawing before release.
Inside this book
Chapters
- 01The drawing as a contractWhat a mechanical drawing must do, which kind of drawing to make, how the AS 1100 standards fit together, and how a drawing differs from the model it came from.
- 02Sheets, title blocks and scalesChoose a sheet size and scale that keep a part legible, set up grid references and a title block that answer the reader's first questions, and stop people scaling prints.
- 03Lines and lettering that survive the printerUse the line types and line groups of AS ISO 128.24 and AS 1100.101, choose widths and character heights that survive reduction, and resolve coincident lines correctly.
- 04Projection, view selection and the projection symbolChoose the fewest views that define a part in third-angle projection, mark the projection method, label views correctly and see how a first-angle reading mirrors a feature.
- 05Sections that show the inside clearlyPlace cutting planes, hatch cut surfaces and choose full, half, part, revolved and removed sections, following AS 1100.101, so the inside of a part reads without hidden lines.
- 06Dimensioning for function, once and only onceLay out dimensions to AS 1100.101: symbols, projection and dimension lines, leaders, numbers and units, functional origins, auxiliary dimensions and the cost of redundancy.
- 07Tolerances on the drawing: general notes and explicit limitsCover every feature with a general tolerance note, pick out the features that need explicit limits or geometric tolerances, and see how a general tolerance on a bearing bore fails.
- 08Surface texture symbols and what they ask forRead and write AS 1100.201 surface texture symbols: the three basic symbols, preferred Ra values, process and cut-off notes, simplified notes, and the inspection setting that changed a result.
- 09Threads, centre holes, seals and other conventionsRepresent screw threads, repeated features, centre holes, springs, gears, bearings, seals and knurling by AS 1100 conventions, and specify them by standard rather than by drawing.
- 10Checking, revising and releasing a drawingCheck a drawing systematically before release, record revisions so every reader knows what changed, and keep superseded prints out of the workshop.
References and source notes
The manuscript and worked examples are original KEVOS® writing. References inform particular concepts; their authors do not endorse this book. Web references were consulted on 25 October 2026.
- Standards Australia, Committee ME/72. AS 1100.101-1992 Technical drawing, Part 101: General principles (reconfirmed 2014) (1992). Supplied copy read for sheet sizes, grid referencing, title block content, lines, lettering, scales, projection, sections, dimensioning and conventional representation. Individual values are cited by clause; no tables or figures are reproduced. The Standards Australia store listed it as pending revision when checked.
- Standards Australia, Committee ME/72. AS 1100.201-1992 Technical drawing, Part 201: Mechanical engineering drawing (reconfirmed 2014) (1992). Supplied, licensed copy read for general tolerancing (Appendix A), surface texture indication (Section 3), centre holes, springs, gears, bearings, seals and knurling. Individual values are cited; tables are not reproduced.
- Standards Australia, adopting ISO 128-24:1999. AS ISO 128.24-2005 Technical drawings, General principles of presentation, Part 24: Lines on mechanical engineering drawings (2005). Supplied copy read for line types, their applications and line groups in Chapter 3. ISO has since published a later edition of ISO 128-24; check which edition your contract calls up.
- Standards Australia and ISO. Standards referenced but not read: AS 1101.3 (welding symbols), AS 1913 (centre holes), AS 2075 (gear terms), AS 2536 (surface texture), ISO 286 (limits and fits), ISO 1302 and ISO 21920-1 (surface texture indication) (editions as called up by the drawing or contract). Named by number and scope only, where the AS 1100 parts refer to them or where later practice differs. No values are quoted from them.
