slightly dif but on the same subject…..

I often looked thru the door of Crossley's Diesels in Manchester…..

huge engines and all crankcases were fabricated from plate…..

then I worked at a company that odered something similar to the above but a complicated hollow sphere

about 5m in diameter from cast steel….walls about 50-60mm thick..they were poured in Norway…..

The tab and slot location system is very similar to the Steven's Patent for producing fabricated diesels engine crankcases introduced into Britain at the Olympia Exhibition of 1931. Here the firing loads are carried through the vertical plates from the cylinder head to the main bearings without loading any welds. Some of the submarine engines of that period were constructed in this way.

Fabricated crankcases are also easier to repair if one should suffer a mishap, more than can be said for an iron casting.

The only drawback to fabrication is that it requires more work to get it to the machining stage, with a casting, once you have a pattern, it is a fairly quick process to make more castings. Probably not much in it for a one off project.

The MOD used to favour fabricated steel crankcases for shock loading purposes in their ships, but I think that may no longer be the case as modern resilient mounts can now attenuate some of the load.

The original Paxman Ventura and Valenta engines were fabricated mostly from pre-machined steel plate, although the more complex shaped drive end gear housing was a steel casting, as were the main bearing plates. Later HST train engines were however, SG Iron castings.

Nothing wrong with a fabrication, just think, they don't cast submarines!

Neil