Manufacturing / Authored KEVOS® book
Fixtures That Repeat
From locating decisions and load paths to a qualified production method
Design and qualify a repeatable fixture using explicit constraints, force and stiffness checks, machining access, trial data and controlled maintenance.
Start reading →About this book
A fixture is a physical agreement about where the workpiece belongs, which loads it can resist and how an operator repeats the set-up. A drawing of a plate and several clamps captures only part of that agreement. The rest lies in contact conditions, tool access, verification, cleaning, wear and the response when something changes.
This book follows a fictional machined inspection bracket through fixture development. The blank is nominally 150 mm by 80 mm by 16 mm. A primary support face, a long side and an end provide its starting references. The exercise is to machine a repeatable feature pattern while leaving a method that another competent person can understand and verify.
All dimensions, loads, test results, quantities and financial values are invented for teaching. They are not KEVOS® projects or performance claims. The force examples are simplified static models with explicit assumptions; they do not establish a safe clamp selection, machine program or production approval for a real installation. Manufacturer ratings, actual load envelopes, machine instructions and a competent application review remain necessary.
The ten chapters produce connected outputs: a fixture brief, a contact map, load and deflection checks, an access review, a trial record, an operating method and a maintenance decision. Each exercise includes an answer or an explicit basis for assessing it. Money examples use Australian dollars and exclude GST.
An original application of established mechanics
READOS already introduces jigs, fixtures, workholding and manufacturing quality. This book concentrates on how to qualify one fixture through a continuous technical case. Its value is in the connections between decisions, including the results that require a design to be changed or a claim to be narrowed.
The supplied handbook informed the topic review. Primary references are cited for the limited principles and equations used. No source drawings, catalogue tables, distinctive examples or chapter structures have been copied. No manufacturer endorses the teaching fixture, and no catalogue part is implicitly approved by appearing in a discussion.
The case concerns stationary machining workholding. Rotating fixtures, lifting devices, pressure equipment, welding distortion and safety-related control systems require additional analysis outside this book. Use the method to ask better questions and record better evidence; adapt the engineering to the actual equipment and consequences.
Who this book is for
Manufacturing engineers, tool designers, machinists and production leads who need to turn a promising workholding concept into a documented, repeatable production method.
What you will learn
- Separate locating, supporting and clamping functions and trace forces through a fixture.
- Check simplified reactions, friction and deflection while recognising the limits of each model.
- Plan access, changeover and trials that distinguish fixture behaviour from measurement error.
- Build an evidence-based release, wear response and spare-parts plan for a controlled fixture.
Contents
- 01Define the fixture as a production method
Write a fixture brief around functional references, process loads, operator actions and acceptance evidence before selecting plates and clamps.
- 02Locate the part without overconstraint
Map rigid-body freedoms, separate locating contacts from supporting contacts and evaluate the effects of locator spacing, clearance and loading sequence.
- 03Draw the load path before sizing the clamp
Use a free-body model to calculate fixture reactions, detect contact loss and distinguish a useful static check from a complete workholding qualification.
- 04Choose clamping force that reaches the part
Evaluate friction, strap-clamp leverage and contact pressure, then specify how the required clamping condition is achieved and checked in practice.
- 05Control deflection as well as strength
Screen fixture deflection with a simple beam model, compare support and thickness changes, and identify joint and workpiece compliance that the model omits.
- 06Make the toolpath and fixture agree
Review complete tool envelopes and reference transfers, calculate an illustrative feed time and account for the handling and inspection work around the cut.
- 07Separate fixture repeatability from measurement noise
Design a controlled reload trial, preserve operator and sequence information, and distinguish fixture behaviour from measurement variation and production capability.
- 08Make correct loading and changeover repeatable
Turn fixture knowledge into controlled operating and changeover instructions, with clear checks for part identity, seating, program selection and abnormal conditions.
- 09Control wear, spares and return to service
Connect fixture wear limits to dimensional function, evaluate a simple wear trend and plan spare parts and requalification without treating forecasts as guarantees.
- 10Qualify the fixture and the business case
Complete a fixture review, distinguish unresolved technical gates from economic estimates and calculate a transparent batch-level capacity and payback comparison.
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 20 October 2026.
- Erik Oberg, Franklin D. Jones, Holbrook L. Horton and Henry H. Ryffel; Christopher J. McCauley, senior editor. Machinery's Handbook, 29th edition (2012). Industrial Press. Supplied reference reviewed selectively for the subject map, dimensional location and workshop measurement background. No fixture drawings, tables, machining recommendations or prose are reproduced.
- Carr Lane Manufacturing. Locating and Clamping Principles for Jig and Fixture Design (current engineering resource). Reference for the distinction between locating and clamping, contact placement and directing loads into support. This book uses its own case, coordinates, equilibrium calculations and trial method.
- David Roylance, Massachusetts Institute of Technology. Beam Displacements (2000). The lecture note dated 30 November 2000 supplies a reference for the standard simply supported beam equation used in Chapter 5. No lecture illustrations or examples are reused.
- Sandvik Coromant. Milling formulas and definitions (current technical reference). Reference for spindle-speed, table-feed and ideal machining-time relationships in Chapter 6. All chosen inputs are teaching assumptions, not recommended cutting data.
- NIST/SEMATECH. Gauge R & R studies, NIST/SEMATECH e-Handbook, section 2.4 (online handbook). Supports distinguishing repeatability, reproducibility and other measurement effects. Chapter 7's short reload trial is not a formal measurement-system approval.
- NIST/SEMATECH. What is Process Capability? NIST/SEMATECH e-Handbook, section 6.1.6 (online handbook). Further reading on why a short successful trial does not establish stable long-run capability.
