Hi Adam,
It depends on the sort of cylinders you want to machine. If you are
asking about normal outside cylinder slide valve cylinders, the way I
machined a set for 'Flying Scotsman' is as follows:

The casting was set up in the 4 Jaw chuck with the cored bore running
as truly as possible and the rear end outwards. You may have to clean
the casting up a bit with a file to ensure it can be held securely.The
cylinder was then bored out to size and the rear end faced off. This
ensures that the rear cover bolting face will be truly square to the
bore. The casting was then reversed in the chuck and the front end
faced off. It's not so important for the front cover bolting face to
be exactly square with the bore.

The casting was then bolted vertically to an angle plate mounted on
the lathe faceplate using a long bolt through the cylinder bore and
suitable packing to avoid damage to the machined ends. The casting was
set up with the bolting face parallel to the faceplate and the rear
face against the angle plate. The bolting face was then machined. The
casting was then rotated through 90 degrees and the port face
machined.The 90 degree angle can be easily set with a square on the
faceplate and bolting face. This method ensures that the bolting face
and port face are truly square with the cylinder bore.

The ports are then marked out and cut, followed by drilling the steam
passages.

The valve chests can be machined in the 4 jaw but the top and/or
bottom faces may have to be milled if the bosses are larger in
diameter than the thickness of the chest. The valve chest covers are
often supplied as a casting which can be carefully machined in the 4
jaw again but frankly it's much easier to make them from brass flat!

If you look on my website at the Flying Scotsman pages
(http://www.baggo.copperstream.co.uk/me/locos/25inch/A1/A1-4.htm)
there's a few photos of the machining operations.

The above process is not the only way by a long shot but I found it
relatively easy. I am sure others will have their own pet methods.

John


--- In halfinchlivesteamforum@..., "xenomorpheus_smith"
<smitad0@h...> wrote:
>
> Hi All
>
> What is the correct order of machining cylinder castings?
>
> Regards Adam
>