build light

I have seen many examples of spun aluminum and it is not made using what I consider the usual machining techniques. At least I don't think it does...

This subject of spinners has me thinking that a really lightweight spinner could be made using this process and use a backplate of plastic or aluminum. I can usually spot spun aluminum as a product as it tends to be very thin, thinner than one usually sees from turning a piece.

So how is this done? How is it shaped? Does it require specialized equipment and skills?

Robert

vicman

My Feedback: (10)

It does use specialized equipment in a production setting. You can wing it if you have an engine lathe but it requires a good bit of tool pressure to move the metal. Basically you start with a flat sheet and use rollers or other burnishing tools to push the metal into the shape you want.
I have used these guys before.
http://www.wenzelmetalspinning.com

ptulmer

My Feedback: (5)

It can be done on a lathe. It's done using a disc of material that is then pushed over a mold. On a small scale it can be done by hand. The tools are pretty long and you need leverage. Here's a link on wikipedia: http://en.wikipedia.org/wiki/Metal_spinning

Here's another good'un: http://www.franjometal.com/metal-spi...-spinning.html

Whirlyspud

You never made an ash tray in 8th grade metal shop did you.

Mike

vicman

My Feedback: (10)

The vid is pretty cool. It takes longer to do than what was shown.
I have done it with roller tools in the past.

heli_Rod

Also a note of interest....metal spinning is an art form if free hand formed. It can also be very dangerous if you don't know what you're doing. CNC equipment is replacing the human touch in a lot of forming shops now. A shop I used to work for spun stainless steel and aluminum parts for jet engines. It was amazing to watch the craftsmen.

Rod

BMatthews

That was an excellent video. He made it look easy!

From the little I know about spinning metal it's important to start with a fully annealed blank. And some spinnings need to be done in stages with annealing between to avoid work hardening. In the case of that spinner you'd have to start with a T0 temper. The T0 spec meaning that it has not been hardened or otherwise heat treated at all. And obviously in the case of that spinner he had to start with a thicker metal than what he needed for a finished wall thickness. There was a LOT of stretching going on as he pulled that thing up the form.

Sneasle

Hey guys, MPI (and a few other I think) have started producing aluminum spinners designed for electrics. As far as I know they are spun aluminum with a plastic or aluminum back plate. Look a bit and you might find them. Should be interesting, might be useful for us guys with smaller planes who would like an aluminum spinner with out the extra weight.

rainedave

My Feedback: (1)

I also enjoyed that video. Maintaining a constant thickness must take quite a bit of practice.

ptulmer

My Feedback: (5)

Bruce, it's amazing how some metals will stretch like that. One of the "secrets" in my job is if you need some more length in a jumper wire, you pull on it and scrub the wire with your screwdriver handle real fast. Start rubbing about a 4" section, when the wire starts stretching you continue down the wire. Just doing that can as much as double the length you worked. (just don't let a peer catch you doing it!)

BMatthews

PT, I know some local telephone guys that will do the same thing if they are short of jumper wire. Or I DID know them. I worked as a weekend warrior telephone I&R guy for the local complany back in the 70's while going to our local tech college equivalent. The guy that took me out for a whopping two days of training showed me that trick and I later hearf about the rack rats doing the same thing rather than run 200 feet of new stuff if a jumper was short by a few inches.

And that was back when we still had a lot of the old step by step Strowager exchanges.....

.....oh god, I'm old......

build light

Heh! No, I chose band for my elective in the 8th grade. In high school it was band and mechanical drawing for four years. I didn't get to make my first ashtray till I went to the University of Alabama on a visit to the engineering dept and it was made in the foundry.

Well! I must say I am glad I started this thread because my eyes have been opened!
Yes, the video was great and it did look easy. Of course a real master of most anything makes whatever they have mastered look easy. It is also a nice coincedence that the video was of a spinner! Notice too that the guy in the video in true craftsman form had to occasionally feel the work with his fingers from time to time.
Still It does look possible if one had at least some of the right equipment. I wonder how the beaded edges are formed?

So has the video made anyone froggy enough to jump in and play around with this idea? On such a small scale it may be a little easier. Mind you I said a little easier.

I just love the things I get to learn in this hobby. I am glad more than myself has gotten at least a little something out of this thread.

Thanks for all the replies and comments!

The first example of spun aluminum I remember well at home and there was just something about the way it was made that just made me think it was special. Light, strong and most importantly, useful.
Robert

heli_Rod

The beading is done by rolling the edge over a form or using a special bead form tool.

You know.....some of your wife's pots look like they could be used to make cowlings. Does she know you're eyeing them?......LOL

Rod

ptulmer

My Feedback: (5)

Bruce, I can take you to a step switch right now. Who would still use something that outmoded you ask? The FAA.[X(]

BL, ribbit. I've got all the materials to do it. Just gotta make the final adjustments on the Smithy and I'm in business.

mapnet

As a N.Y.Telephone Co. Large Job Installer in the 50's&60's ,I used to build up 701 and 740 PBX's from piece parts.

Maurice

GrahamC

I liked your second link.

There is a show here on the Discovery Channel (Canadian version) called How it's Made. They did a segment on metal spinning and as soon as I saw the pictures on the second link for Franjo Metal I recognized the guys doing the hand spinning - the video is part of what was broadcast on the show as well.

Neat stuff. Almost magical.

cheers, Graham in Embrun near Ottawa Canada

BMatthews

Oh yeah.... that really makes me feel safe about flying....

How have they managed to turn a blind eye to all the modern calling and voicemail features that come with electronic switches? I suppose they still do all their typing on old mechanical Underwoods as well?

ptulmer

My Feedback: (5)

It's the emergency ringdown for the region. (now you reeeally feel safe) They've got newer (relatively) stuff for everyday use. Up until a couple of years ago, we had to go clean the relays every six months. I don't think it was replaced, we just don't have anybody that knows how to clean them anymore. I just got rid of my last 1A2, too. This part of the country is a technological graveyard.

build light

On the stunthager forum I saw a new thread for these new one inch diameter spinners made from spun aluminum for half A use!
Looks really sweet but a little pricey... Still where are yougonna find another like it at any price?

Quote:
"Check out the latest product in stock.
One inch diameter spinners.
Spun aluminum cone with a turned backplate from 6061- T-6 alloy. The nose piece has a 1/16" cross hole to tighten, with a 5-40 stud to fit into the supplied union nut. These are fit together as a set.
No prop cut outs. The assembly weighs just under a quarter of an ounce.
Price is $20 with $2 shipping"

Not sure where they are available from yet but when I find out I will be happy to share that info.


Robert

P.S.
Here is the source for this spinner:
LEE MACHINE SHOP

827 SE 43rd Street

Topeka, Kansas 66609

785-266-7714 --- [email protected]

ptulmer

My Feedback: (5)

They look handmade, so twenty bucks ain't bad.

TFF

The old Froom spinners were spun, and I think someone had the like through the 80's. You just dont want to hit it with an electric starter; it would probably blow apart.

gkamysz

My Feedback: (19)

Unless you are making thousands of tiny spinners you might as well use bar stock. The material savings in a 1" spinner is very small. I worked for a company that purchased spinners made in China. The spinners were forged to a rough shape then CNC turned to final shape. This was much better than the previous supplier that used cast aluminum that was turned to shape. Spinning would be much more practical for larger spinners. One would need to evaluate the cost to see where the breaking point is.

ptulmer

My Feedback: (5)

Greg, I'm surprised to hear something like that. Spinning it should result in much, much less material per spinner. Plus you are reducing the tooling, etc. What is it that I'm missing?

KidEpoxy

Dont forget the substantial drop in the sweeping chore by using the kerf free spin method.
I for one hate the transdimentional activities of them little metal shards,
you sweep an area, put the broom away, and the little metal jerks pop out of thier subspace pocket-dimention to stab you in the finger when you are putting the cover on the machine. I know they werent there when I was done sweeping, and presto- they just materialize for the attack. So small, so shiney... so evil. SpiralKerf: The Phantom Menace

vicman

My Feedback: (10)

Patrick notice he was having them forged (beat to shape) and just finishing them up in a lathe. With a decent turning fixture this is a great cheap fast way to make them. They would come out pretty close to the same weight and be a good deal stronger from the forging process vs being deformed in spinning.