Welcome to Iain Macleod Associates

Iain Macleod Associates Ltd has been providing training and consultancy services for industry since 1991.

We are the UK’s leading provider of training in Geometrical Tolerancing, Geometric Dimensioning and Tolerancing (GD&T), ISO Geometrical Product Specification (ISO GPS), BS 8888 and mechanical specification. We provide training courses on-site for a wide variety of clients, spread across a broad range of industries.

Our courses are certified by the Institution of Engineering Designers, and are available as accredited courses through the National Physical Laboratory training framework.

We are an approved supplier to BAE Systems.

We provide training throughout the UK and Ireland, and also run courses in Europe, the Far East and South Africa.  We run several public courses each year which you can book individual places on.

For more information regarding our courses please visit our courses page.

All courses are available for online as well as on-site delivery.  Online training has many benefits:

  • Free of geographical restrictions – delegates can participate from diverse geographical locations
  • Resource-light – delegates can participate from home, from their desks at work, or even from a beach! No special training facilities are required.
  • Low carbon footprint – no travel required for trainer or trainees
  • Lower cost – we charge less for online training


We are looking for someone to join our training delivery team on a part-time basis.  Training can be provided.  Please contact us with details if you are interested. Requirements:

  • UK-based
  • Willing to travel
  • Suitable engineering degree or apprenticeship
  • Relevant experience in design, manufacture or metrology
  • Good presentation skills

Iain Macleod is the chair of ISO Technical Committee 213, which is responsible for international standards for Geometrical Tolerancing and Geometrical Product Specification.  This is an active technical committee, comprising around 15 working and advisory groups, with the participation of around a hundred experts from over 20 different countries.  Within TC213 he acts as convenor on Working Group 17, is the UK principle expert on Working Group 18, and also chairs Advisory Group 1 for strategic planning.

He is also chair of the BSI Technical Committee TPR/1, which is responsible for British Standards in the area of Technical Product Realization, and subcommittee TPR/1/8, which is responsible for the development and maintenance of BS 8888. 

Welcome to Iain Macleod Associates

Iain Macleod - Managing Director

Clients we work with include:

BAE Systems
Martin Baker
James Fisher
Bombardier Aerospace
Honda F1 Racing
FMC Technologies
Surrey Satellite Technology
Ansaldo NES
Marshall Aerospace and Defence Group
National Physical Laboratory
Reaction Engines
Fusion 4 Energy

Our Services

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We provide training in the following:

  • Geometrical Tolerancing to BS 8888 & ISO Standards
  • Geometric Dimensioning & Tolerancing (GD&T) to ASME Y14.5
  • Geometrical Product Specification (ISO GPS)
  • Engineering Drawing
  • BS 8888
  • Tolerance Stack Calculations

Most of our training courses are delivered on-site for clients, but we also offer a small number of public courses each year, which you can book individual places on. We can provide training which is accredited by the National Physical Laboratory, and certified by the Institution of Engineering Designers.


Find out more
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We offer an advisory or consultancy service for clients, to deal with queries about any aspect of tolerancing or product specification.  Contact us if you need assistance in any of the following areas:-

  • product definition
  • interpretation of tolerance requirements
  • application of standards
  • tolerance analysis
  • definition and implementation of datum systems
  • development and mentoring of technical staff
  • assessment of suppliers
  • etc
Find out more
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The GPS Pocket Book is an A6 sized booklet which provides a summery of the key elements of the ISO GPS system. Written by Per Bennich and Henrik Nielsen, both former chairmen of the ISO technical committee responsible for standards in this area (TC213), this is the best pocket book currently available if you want a compact, concise and up-to-date summery of the ISO GPS system. The Pocket Book is available at half-price for educational institutions.

Find out more

Resource Centre

The articles below provide some background information about Geometrical Tolerancing, Geometrical Product Specification and the standards that underpin these subjects.