Welcome to Iain Macleod Associates

COVID-19 VIRUS UPDATE: in response to the restrictions currently in place, we have been exploring the options for delivering on-line training courses, and are pleased to announce that we are now able to offer this option for all our courses.  This does require some changes in approach.

  • Materials such as course notes are posted out to delegates in advance.
  • The courses are broken down into shorter sessions and delivered over a longer period (e.g. our three day courses are spread over four days, which do not have to be consecutive).
  • The courses are conducted as a series of live sessions using Zoom (other systems can also be used), each lasting between 1.5 and 2 hours.  Two or three of these sessions would take place on each day of the course.

If you are interested in on-line training, please contact us for further details.

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.

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
FMC Technologies
Honda F1 Racing
Surrey Satellite Technology
Ansaldo NES
Marshall Aerospace and Defence Group
National Physical Laboratory
Reaction Engines
Fusion 4 Energy

Our Services

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

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

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.