...I will try and answer a few queries before the next post.
Firstly; Hovis, you are not so far with your summary. It is indeed a tricky procedure and you really need three hands! One to operate rotary movement, one to operate the motor and another to move the cam. I actually put the first try into the scrap bin after quite a few hours work-but that's how it goes. In order to learn, you have to make mistakes and sometimes these are expensive ones, but it all serves to drive the lesson home! You just get a little depressed, sit down and take a deep breath, then just write it off and pick up another billet of metal.
Scrap and swarf. Yes, I produce a lot of both. One reel usually makes enough aluminium alloy swarf to fill two rubble sacks. When I have a few sacks, it's a trip to the local scrap/recycling centre. What happens then, I do not know but presumably it somehow becomes re-used.
Until fairly recent years, it was the practise to make complicated shapes, such as reel backs-even spools-carburettors, kitchenware, electric drill & motor bodies from hot castings, using an easy-flow metal alloy nicknamed 'Mazac' which could mould the most delicate shapes and lettering even (see the "engraving" or "stamping" as it is called, on some reel backs). The downside is that any cast metal is not 'poured', but injected into a mould to fill the tiniest area and so is very dense-and therefore very heavy. Cast Duralumin is immensely strong-but oh so heavy!
Casting also means making multiple moulds, many of them, which is all expensive time and money.
Today, CNC machining is so brilliantly accurate and quick, it is far more economical to make shapes from a solid billet or piece of metal-or any other material, with the added bonus of knowing that when something breaks, only the current item is scrapped, not an entire batch. The other plus is that there can be no blow holes or hidden casting flaws. Modern materials are also much better and far lighter. To give you an example, I have almost finished the first Aerial-Match reel back and even now, it is over a third lighter than the original. Hardy Bros. used to make their reels from machined castings. Then they realised that, even including the scrap, they could make them from solid "barstock" material at a fraction of the cost!
Aluminium and it's alloys are made from Bauxite, which is the commonest metal ore in the Earth's crust, but it is expensive to get out! A bit like the gold in sea water, but less so.
Nobby; You asked about why the tool is in the lathe chuck?
It is merely a question of axes (plural of axis, not the weapon!) In order to cut a certain way, you have to 'think outside the box' to use a modern idiom. The lathe has two axes of movement, 'X' and 'Z'. i.e. across and right to left, but not UP! If I want to cut in this direction, I have to change things around to suit. The trick is to figure out first what you have to do, then work out the best way of doing it. I am trying to do a four axes job on a two axes machine, so have to improvise. The reason for the two angle plates is because the lathe is too small for the job in hand. If it was a four inch lathe instead of a 3 1/2" one, there would be a much easier way of doing it.
..Now back to the Aerial-Match backplate..
The last job was taking it down to thickness. I left the centre stub on to assist grip. Apart from drilling the holes, the last tasks will be to radius off the edges and produce the centre boss. The radii on the edges took about seven hours of hand filing alone. There is no other way for me to do it. There are still a lot of scratches to polish out but these are merely cosmetic.
Here are a few pics of the penultimate stages..
This virtually completes the first one and it's look a bit like the real thing now!
I have already started on the line drum and taken some pictures, but will have to take a break from this for a while now... stay tuned in
wm+