Freesteam

Spokesmann · Posted: Tue Dec 30, 2008 1:08 pm Post subject: Base(ics)

...or the comparison of flatbase and early raised base Mamods.

Looking at the pictures you can see the variety of baseplate shapes and sizes that proliferated before the war and just after - into the 1950s. It's my view that not until the mid-1950s, or approximately the time of the introduction of the raised based engines proper (the MM1 had one from c1949), did Malins Engineers really start to get to grips with standardisation of parts, of which bases was one. As you can see from the images the flat base engines have a variety of sizes, the images do not include the post war SE2 with countershaft which had another size too or the pre-war SE3 (Mike MC can you post an images/size?) or the SE4 prototype which had the biggest flat-base of all engines. Apart from the MM1 (5.6" x 3") the smallest base manufactured for a base-mounted engine was the pre-war and immediate post war SE1 which had a base of just 14cm square or approx 5.6". The pre-war MM2 twin had two base sizes, of which my MF replica is the smaller type at 6.5cm x 11.5cm (2.6" x 4.6") - Ian can supply details of the larger base variant.
We see also the post war SE1 (with regulator/oddity) and its bigger brother the SE2 - both from 1948, however the base sizes are 16.5cm square (6.6") and 16.5cm x 19cm (6.6" x 7.6") respectively. The SE4 (and possibly the SC4) shared the same base-plate size as the 1948 SE2. These dimentions could have varied too for all pre-war Mamods were essentially hand-made, base-plates being hand drilled and possibly cut to size (more info required).
It's not until the raised bases come in that we see some degree of standardisation as the 1954 SE1 and SE2 engines have bases measuring 18cm x 21cm (7.2" x 8.4"), this size being maintained right up to the last SEs of 1978/9. The SE3 being the largest base-plate they made at 24cm x 26cm (9.6" x 10.5")
[Note: raised base engines measured across the feet].
Some standardisation did exist before the 1950s with the flat-base lineshaft sharing a base with the post war MM2. The raised based MM2 sharing the same base-plate as the raised base lineshaft after 1954.
Much later the new SP engines shared bases too, the SP5 MK2 being the same size as the SP4.
Please add any other dimentions or key facts about standardisation of base parts as necessary!

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Mamod Collector · Posted: Mon Jan 05, 2009 7:59 pm Post subject:

The base measurements of the SE2 Circa 1946 are (W,L)
16.5 cm x 19 cm Smile

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Mike
My personal website, with pics. Smile

www.mikes-steam-engines.co.uk ™

Mamod Loco Smile

MFSteam · Posted: Mon Jan 05, 2009 8:19 pm Post subject:

Come on guys these are made in Imperial dimensions. Holes are 5/32" diameter on a 1/2" pitch with the hole centreline 1/4" from the edge. Well thats the theory anyway Very Happy