Quote Originally Posted by angrybear View Post
Circlips need a recess to sit in which requires more machining, which needs very tight tolerances, the hole for the pliers to open/close them also requires space,
Where an "E" clip is a single use spring/interference fit & the design means that if the pin tries to pull out it actually digs in more, to get a tight fit you just press it on, job done
I think you may be getting mixed up between E clips and star locks

http://www.modelfixings.co.uk/circlips.htm