Machining an angle plate casting without the use of another fully machined angle
plate would appear a non starter. However, it can be achieved easily by using two
The squares can be easily, and accurately, made in the workshop enabling a precision
angle plate to be machined. The casting in the photograph (seen already machined)
is supplied by The College Engineering Supply. Castings are though supplied, and
in range of sizes, by a number of suppliers to the home workshop and the method would
be equally appropriate for any of them.
The details for making the cylindrical square and the method
used for machining the casting are published in my book
"Milling a Complete Course"