Marine Compound Engine

March 2010.

John R. Bentley 2010.

Castings Set

-  for the Stuart Compound Launch  -

This page may prove to be quite an eye-opener if you haven't looked at raw castings before. These are not to be confused with investment (or lost wax) castings, nor will they resemble the apparent beauty of finished castings - that transformation is our job. Just take a look as some of my close-up pictures. The foundry doesn't make the part, that is the task of the machinist. The foundry's job is to provide enough metal - only where it is needed - to allow construction of the part - and that's it. Casting is an art in itself and many years of experience pays off in producing good castings. Among a host of other foundrymens' concerns (including human safety), allowances must be made in advance for shrinkage of the metal during cooling. To me, a well made raw casting is evey bit as beautiful in a different way as its machined counterpart.

Please wait until this picture loads

Let's have a good close look at the cylinder block first.

There are sixty-two holes to drill in this block of iron and all but five are also required to be threaded. For each of them there is an equivalent hole to be drilled in another piece. In addition the top, bottom and both ends are to be machined, exhaust ports must be milled and the cylinders are to be bored out and lapped. At that point this casting will be finished.

Think that's a crack in the casting?

Not at all!
Here is the same casting partially machined two weeks later

I know there is going to be some trouble here...

Back to

Compound Launch main page


                 Castings, Materials and Fastenings 
(this page)


Cylinder Block

Top Covers

Bottom Cylinder Covers

Steam Chests

Crosshead Guides and Bracket




Connecting Rods and Crossheads

Main Bearings


Fittings: Oil Cups

Fittings: Drain Cocks

Fittings: Exchange Pipe, Flanges and Glands

Stephenson Link Reversing Gear (5 pages)

Completing and Erecting the Compound Launch Engine


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(c) John R. Bentley 2010.