The top and bottom joins are rolled edges - done with a set of two shaped rollers in a top & bottom seamer that clamps the top and bottom in place against the rolled edges of the body. First stroke rolls the body edge over the top of the top (or bottom depending which way up it is), the second stroke flattens it against the side of the clamping plate at top. Each end is done individually.
The top and bottom pressings are round with a depressed edge all round.
The body is a rectangle of sheet steel with the points notched, ie cut at an angle, so that they don't catch or foul the edge roller when rolling the top & bottom edges.
Same manufacturing technique as making the great Aussie 'Billy' can, and I've made plenty of them during my senior school and university breaks. Of course, that is with the right machinery for the job, but if only making one or two, Grant's methodology and tooling sounds fine.
Mike
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