Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Rules of thumb

Jim Walker's recollection of his old drawing office 3:4:5 rule made me think that there must be many other old 'slide-rules of thumb' now made defunct by modern technology.

Subscribe for full online access and get...

  • Full, instant access to all stories
  • Customised email alerts straight to your inbox
  • Monthly print magazine

Register for guest access to keep reading and get...

  • A free taste of other selected news stories
  • Daily email newsletters

Already have a subscription or ICE membership? or