This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
A scoop (Fig. 1) for a coal-weighing machine should be made of No. 19 S.W.G. best charcoal iron. To mark out the pattern of the body (Fig. 2), first square a sheet of iron and set off along the edge a distance A B equal in length to the required measurement around the scoop. At A and B and at C, which is the centre of the line AB, erect perpendiculars; then set off the distance CD equal to the length of the scoop. From D along the line D C measure D E equal in length to A C. With E as centre, and E D as radius, describe a semicircle as F D G. Then AFDGB will be the pattern required. Extra allowance, represented by the dotted line, must be made for wiring. Cut out the pattern, roll it to shape, and set off the wiring edge. Up-end the scoop on a piece of iron and mark round the pattern of the back. The laps for riveting and the wiring edge at the top, shown in Fig. 3, are additional. Punch 3/16in. holes in the laps, and bend them at right angles to the back; set off the wiring edge also, but in an opposite direction. Fit the back on, mark the holes, punch them, and then rivet the back in place. The scoop should now be wired, the rod being in one piece and meeting in the centre of the back; otherwise the strength of the scoop will be sensibly decreased. A wrought-iron handle is next riveted to the back as shown in Fig. 1. Two pivots, which should be case-hardened, are riveted to the side of the scoop so as to allow it to rest in position on the machine, and also to enable it to be freely turned for delivery.
Scoop for a Coal-weighing Machine.