Moon Disks

So, I'm kinda thinking it'd be cool to make some moon disks, like this
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without the snap-on features and for model airplane use (yes, I'm on
a mission).
These are obviously spun -- but how do they do it? They're spun _all
over_,
which leads to some obvious problems in part-holding. Do they
spin part of it, then change the holder, then spin the rest? What do
they do?
Anyone know? Anyone have a good guess?
Reply to
Tim Wescott
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I've seen some vids where they glue to a wooden form, maybe in this case there is a small center piece that clamps tight enough to form the very central part and also imparts enough pressure the backside form can spin it.
Or, central part is formed in a special op, then it is transferred to another machine.
Dave
Reply to
Dave__67
Tim Wescott Inscribed thus:
I would guess that they are pressed blanks, edge turned over, then polished. The perforations around the inside edge of the rim would be done before the edge is turned over.
Reply to
Baron
Glue might work. The ones I've seen are "spun" right up to the center of the disk, although they may have been formed by other means and then had a tool run over them (as yet another operation, presumably) to get the look.
Reply to
Tim Wescott
The original Moon disks (not the snap-on ones) were just flat aluminum that had been dished on a spinning machine (somehow). You were then expected to drill and tap your wheels for itty bitty screws to hold the disks on at speed.
Whatever the original process was, it was low tech and I want to replicate it (or at least get the look!) in 1.5" diameter on my lathe.
Reply to
Tim Wescott
Glue might work. The ones I've seen are "spun" right up to the center of the disk, although they may have been formed by other means and then had a tool run over them (as yet another operation, presumably) to get the look.
Reply to
Ed Huntress
Tim Wescott Inscribed thus:
I recall seeing some 35mm dia, dome shaped, polished control knob inserts kicking about. They were stamped out of 0.2mm thick aluminum. I'll see if I can lay my hands on them.
Reply to
Baron
Ive heard of people making these for RC cars from the bottom of an aluminum soda can.
Reply to
DougC
I was figuring that since I'm doing it with thin material for an itty bitty part, I could get away with it even if my lathe is cheap and Indian.
Reply to
Tim Wescott
The originals were done in a 3 step process. The blanks were laid out and cut and the holes drilled. Then they were mounted to a spinning form with screws and spun into the form with a wheel tipped tool. Then they were removed and mounted to the finishing form and spun to the final shape and finish on the face. The two forms were basically mirror image wood initially, then they turned steel ones.
For what you want the easy way would be to press spin them. Make a two piece form out of steel. The outer form will have a dish in the shape you want, this one will be attached to an adapter that will fit a drill press chuck. Now make a mirror image one that will get mounted to the vice/table. To use take your aluminum stock and with the press running at a middle speed, just act like you're drilling holes. Coating the aluminum with some LIGHT lube will make it easier.
Reply to
Steve W.
I was figuring that since I'm doing it with thin material for an itty bitty part, I could get away with it even if my lathe is cheap and Indian.
Reply to
Ed Huntress
Tim - these show a bit:
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Reply to
Dennis
All I needed to know.
Man, I love watching metal spinning videos. It's just like magic.
Reply to
Tim
My first attempt at spinning was to make 1/12 scale drop light shades for a client. I used a unimat 3 lathe with a hardwood dowel form held in the chuck and a pressure plug on a live centre in the tail stock. My forming tool was apiece of 1/4" rod cut at 45 degrees then rounded and polished. I started out with the cupped bottom of a soft drink can and it was only after I had finished that I realized I had been using steel instead of aluminium cans. I suspect that these cans were of special soft alloy. Anyhow these turned out very nicely and sure impressed the client. Gerry :-)} London, Canada
Reply to
Gerald Miller
Gerry -- I had been wondering where I might find the right aluminum, and hadn't even considered pop cans. D'oh. That's perfect!
Reply to
Tim Wescott
Ed,
In spinning wrinkling usually results from trying to move the material to much in a pass and it wrinkles rather shrinks. It can be recovered if not excessive but best to avoid it altogether. Shame your uncle died before you got to spinning as it's quite an enjoyable thing to do I find.
Reply to
David Billington
Yes, it's something I'd like to learn some day, because it does look like a fun and useful aspect of the hobby. When I tried it I could feel (and see) the metal shrink at the start, and then, when the curve became steeper as I progressed toward the wide end, I reached a point where it wouldn't shrink, but just wrinkled.
I tried removing the piece and annealing it (it was 3003 aluminum). I could move a little farther down the die block without wrinkling, then it would start to wrinkle again.
Although I didn't learn spinning, I was glad that he had time to teach me faceplate work with toolmaker's buttons and lapping, both of which seem to be disappearing skills.
Reply to
Ed Huntress
What are toolmaker's buttons?
Reply to
Tim Wescott
What are toolmaker's buttons?
Reply to
Ed Huntress

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