The Sequence for Machining Castings
This item is dual purpose, a guide to machining castings in general but at the same
time illustrate this by machining a Keats angle plate. It is therefore listed in
both my Project and Process lists. Its main purpose is though to illustrate how to
proceed with machining a casting, detailing the decisions that have to be made, and
was initiated by a novice metalworker who found it difficult to decide which face
to work on first when confronted with a casting to machine. He was, at the time,
considering the Keats Angle Plate shown in “The College Engineering Supply” catalogue.
To satisfy the need, it would be good to be able to say, “mount the casting in a
manner so that you can first machine the surface that ----” , of course it is not
that simple. The very nature of a casting is that its shape is likely to be in most
cases quite different from any other casting the workshop owner is likely to be called
upon to machine, the Keats Angle Plate being a good example. This having been mentioned
in the original request it is an obvious choice to use as a subject so as to come
up with some pointers for this and other castings needing to be machined.
So as to provide other examples though I have chosen also to machine the Small Vee
Angle Plate. This also from “ The College Engineering Supply”and is provided on the
site as a separate project. Both items are intended to perform similar functions
though the Vee angle plate is more adaptable and will work more readily with smaller
workpieces. I intend therefore, in addition to detailing the setups for machining
these, also to explain their purpose and the pluses and minuses of each design. The
castings as received are shown in Photograph 1, with those for the Keats on the left
and the two for the Vee angle plate on the right. In both cases the hardware required
has to be provided by the workshop owner.
The nature of a casting
I do not confess to being knowledgeable regarding the finer details of casting metal
objects but in this project we are considering just iron castings which are almost
exclusively produced in a sand mould. In very basic terms the mould is made in two
parts that can be separated so as to enable the pattern to be removed when, after
reassembling, the molten iron can then be poured to produce the required shape.
Non UK Viewers
I fully appreciate that for some non UK viewers the expense of obtaining the castings
will make this project a non starter. Even so, the descriptions of the set ups, etc.
should make reading these pages worthwhile, especially for the novice metalworker.