Precision work and accordingly I called on a local bottle-top and washer factory that doesn't have CNC equipment but does have an angle-grinder. If you do this yourself instead of sending it to Percy Adcock as we did, it requires a deft touch and years of training not to cut the washer in half and say 'Fuck'.
The alternative, and the way we'd have done it back in school, is to drill a series of holes that you can file out... but then why have an angle-grinder and bark yourself?
