Have noted two base sizes on ebay items, both listed as 1939, - one base is 10 holes by 6 holes and the other is 9 holes by 5 holes .
The MF twin replica engine I bought recently has a 9 by 5 hole base .
Would appreciate knowing if both are correct please and if a means of dating also ?
Also is the Mamod Minor either engraved or in raised letters an indication of year ?
Thanks
Stuart
I have both sizes, and they are original. Will have to dig them out to help you more...
This is what I have on the shelf. I am no Mamod expert, all I know is what I have read over the years... and from what I have read, that would make these first two pre war Minors as the engine frames are bare brass with silver crank disks and the third post war.
From left to right.
First: has silver painted crank disk, and a steel boiler band with remnants of black paint (9x5 holes)
Second: crank disk is bare metal and the firebox/boiler band have had the paint sanded away by a previous owner (9x5 holes)
Third: I had thought this was maybe pre war, but upon close examination I can find very trace remnants of green paint on the engine frame and a few speckles of gold paint on the "Mamod Minor" stamped crank disk, making it a post-war with a 10X6 hole base. This also has the copper-plated steel boiler band.
Also note that the two pre-wars have a lighter orange-red than my post-war example. I can see a few spots of new red paint on the later one, but it is hard to tell if it's had a repaint at some point... if it has, it was many, many years ago...
The twin was sold with both big and small baseplates.
Post war (10x6) green paint remnants on the engine frame

and gold specks right in the center and inside the "D"

Another thing to note on these earlier Mamods is how the tops have an orange-ish red "Mamod red" where the bottoms are "Hobbies red"

The two pre-wars use the center hole on the long side to secure the boiler band and they both have a spot stamped in the base for the burner tube

You decide if this is a repaint... I can see new splatter over the bare metal corner and the rest looks to maybe have faint brush strokes, but very old

And the boiler band has it's own mounting holes more to one end of the base
Nick - many thanks indeed.
That helps tremendously
Bill