As far as brass Height Adjusters is concerned, they were only fitted on the Series 1 machines and went by the way of the dodo as a cost cutting exercise and replaced with the cheaper and lighter diecast unit.
Another reason for using brass on the Series 1 machines could be, that Scott Bonnar were brassfounders for much of their history. There's a thread on ODK
HERE that mentions their exiting this business in 1974, so does the timeframe for the height adjuster material change seem about right?
