Update 2 - brass spinning

[Matty F]

By request, detailed pictures of spinning a brass lid on a lathe. Here's the finished lid on the left, with the sheet brass it was cut from. The 100 year old original lid is at bottom right, and the other lid I previously made is at the back. It's already become tarnished by sitting on a hot steam engine for a few weeks:

's the circle of brass clamped against the wooden mandrel with a large steel washer: edge has been pushed halfway across by the tool that is free to rotate: didn't use any lubrication as it shouldn't be necessary when using a roller, and I would have to burn it off when annealing.

Since the brass was too hard to spin easily, I had to anneal it half a dozen times during the spinning operation. When the edge starts to get wavy it's time to anneal. Annealing the brass on a brick:

edge is now pushed flat against the mandrel. The brass has to be compressed to get rid of the excess metal on the outside. That seems to work OK. the rough edge: lid in place at lower right on the steam engine:

[robgraham]

ic.com/2eztx8y.jpg

Thanks Matty - I don;t have any immediate requirement but it's good to see how it should be done. All I have to do now is to snaffle your photos onto my pc.

Rob

[Tabby]

ic.com/2eztx8y.jpg

Can we drop that and he pics onto the ukdiy wiki? Then its there for people to learn from indefinitely.

NT

[Matty F]

weeks:

> > Here's the circle of brass clamped against the wooden mandrel with a

brick:

> > The edge is now pushed flat against the mandrel. The brass has to be

engine:

> Can we drop that and he pics onto the ukdiy wiki? Then its there for

Sure. But I don't claim to be an expert, and people told me that this wouldn't work. And I used the wrong kind of brass, because it was free.

[Tabby]

inypic.com/2eztx8y.jpg

NT

[John Rumm]

weeks:

>>>> Here's the circle of brass clamped against the wooden mandrel with a

brick:

>>>> The edge is now pushed flat against the mandrel. The brass has to be

engine:

>>> Can we drop that and he pics onto the ukdiy wiki? Then its there for

Kind of embodies the DIY ethos nicely... not only tight fisted^h^h^h^h^h^h^h^h^h^h frugal, but interrupts the expert commentary about how something is impossible, by actually doing it!

[Tabby]

inypic.com/2eztx8y.jpg

I've been told so many times, including on here, that things were impossible, but done a lot of them were. There has to be a life lesson in that somewhere.

NT

[fred]

In article , Matty F writes

easy.

[Steve Walker]

I dunno, but I find it inspiring that old crafts are still alive like this.

[Matty F]

I have taken careful note of critical comments, and sometimes changed the methods. The roller tool ended up way below the centre of the work and I decided that was a good thing. If there was too much pressure applied, the tool would bend away from the work.

I was impressed by this 1930s example of spinning aluminium. They must have had a very big lathe:

the rest of the device is much bigger, like 50 feet high.

[Dave]

30 years ago, I went to a demonstration that included the spinning of aluminium pans. Each one could be made well within 5 minutes, including the two pouring lips on the side. I suspect the aluminium was of the type that could be solution treated, so as to not go off and harden until after treatment and working. I estimate 60 minutes after solution treatment.

Dave

[Frank Erskine]

I've never heard of "solution treated" aluminium. Have you any details please? Which solution?

TIA -

[Jules Richardson]

JOOI, do you scribe / stamp something on the underside of the lid (or somehow log elsewhere) the fact that it's a reproduction rather than period part? I'm not sure what's typical practice for restoration of engineering items? (I suppose over the working lifetime of the engine it may have had all sorts of tweaks and parts replaced with something slightly different anyway)

cheers

Jules

[Dave]

I used to work in the aerospace industry and the solution treatment was used so that L72 and L73 could be softened to work the sheets to complex shapes. The treatment would last for about 4 hours before the sheet would revert back to the unworkable state.

I can't supply any details, as that was not my area.

L72 used to convert into L73 after it generated an oxide coating on it, giving it a protection against corrosion.

Dave

[Andy Champ]

Clarke's First Law.

[Matty F]

I engraved my name and the date underneath the lid. These are probably the only things that will be left of my work after another 100 years. Except that someone will pinch them and melt them down for the brass! Damn!

[Andy Wade]

I'd never heard of it either, but it seems to be annealing (heat treatment) by another name, and with more precise time/temperature control than you'd get with the traditional "heat until the soap goes black" method:

[Dave]

and L73 can be annealed and it results in a much longer workable time. AFAIR until it gets treated again to make it stiffen up.

Dave

[Andy Wade]

I don't think so. Certainly the 2000-series ('dural' type) AlCu alloys age harden - I remember that from O-level metalwork where we were taught to re-anneal our work if it had been left for a few days.

is interesting.

I've no idea what L72 and L73 are. Can you relate them to modern

4-digit IADS designations?

[Dave]

Is this what you mean... L72 = 2014 T4?

Take a look at this link for more info.

Out of the industry for 13 years now.