We were hoping to have as many early Automatons as possible to the 2020 AGM in order to compare, discuss & debate the various changes during the mowers 18 year production run. In the absence of this I have pulled together various information on a timeline and have placed this on the new AGM forum. https://www.oldlawnmowerclub.co.uk/forum/annual-rally/ransomes-automaton/automaton-timeline
There are probably only around 15 Automatons known to exist, being held by members, museums and certainly one non-member I know. In the figure of 15 I have allowed for 3? being held by Andrew & Mike of the Hall & Duck Trust, & I would invite them to let us know which variations they have & help add to the information we are gathering.
In addition to the changes detailed on the timeline, there are many others including different drive gear configurations as shown in the main images above, it would appear the earlier models had all gears on one side. with internal gear covers on some later models.
Three versions of the cast concave, being solid, with two holes & the removable type.
Handles, at least four machines known have no name on handles, these certainly appear to be earlier design, could they be Ransomes & Sims from the first 2 years of production?
Number of cutting cylinder knives, I know of one with 6, most have 5? Perhaps we need to check in to see how many the known machines have?
Many questions still to be answered perhaps we could discuss on the new AGM forum, I will be happy to amend the timeline with any additional verified information.