Try searching for A Belleville Washer, a Conical Spring Washer, Disc Spring Washer, Wave Spring Washer, Belleville Spring Washer or Cupped Spring Washer
a quick search found these
http://www.springmasters.com/spring-washers.html
http://www.apexfasteners.com/fasteners/stampings/washers-and-shims/spring-washers
and loads of others on Google.
@ObiWomKenobi started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Try searching for A Belleville Washer, a Conical Spring Washer, Disc Spring Washer, Wave Spring Washer, Belleville Spring Washer or Cupped Spring Washer
a quick search found these
http://www.springmasters.com/spring-washers.html
http://www.apexfasteners.com/fasteners/stampings/washers-and-shims/spring-washers
and loads of others on Google.