Update - brass spinning

[Matty F]

I had trouble spinning brass sheet before. The brass came out of the scrap bin so was probably the wrong kind of brass for spinning as it work-hardened immediately it was bent. I managed to spin this brass lid properly, by annealing it many times during the spinning process. Here is the finished oiler lid together with a 100 year old original lid:

's the lid in place on the oiler. The lid is to keep the dirt out of the oil. oiler is at bottom right (by the red crank) on this big 100 year old triple expansion steam engine. The oil lubricates the crankshaft. the brass handle on the lathe: made a curved tool to cut the curved part of the handle since I don't have any fancy gadgets on the lathe for curves.

As in this earlier picture, I used this roller tool that I made, to turn the edge of the brass sheet. This time I removed the brass from the lathe for annealing, about six times, dunking it in water:

was very hard to get the lid off the wooden mandrel when finished. In future I will make a steel mandrel.

I did a few experiments and decided that with the brass sheet I had, it became softer if I heated it red hot and dunked it in water. That also was quicker than letting it cool by itself!

[dennis]

[John Rumm]

ought to do a wiki page of "things that Matty made" ;-)

simply turn it from solid[1]?

Or split the wood one, and use a band round it, and a pair of folding wedges to hold it in final shape in the band.

[1] Used to watch the bods in Marconi's central machine shop turn out casework for some of the more exotic avionics kit. The amount of times they would start with a block of magnesium 18" cubed, load it on a CNC milling machine, and then several hours later remove the finished case, and load the swarf into a wheelbarrow with a shovel was amazing!

[Adrian]

Matty F gurgled happily, sounding much like they were saying:

[fred]

In article , Matty F writes

Did you take any pics of the intermediate stages as you were doing the spinning?

[Matty F]

before. The brass came out of the

I need to make another lid so I'll take some photos of the spinning. Here's the spinning tool that I made (on top of the brass sheet as it happens)

make sure that the tool is below centre, so that if the force applied is too great it will bend away from the work instead of towards it.

[Nightjar]

For spinning, you need an alpha brass alloy, which means it contains less than 37% zinc, such as CZ108.

...

All professionals I've seen doing hand spinning used wood formers, but it was a hard wood and well polished. I suspect that there should have been a very slight taper too, to help you release the lid.

It shouldn't make any difference to brass, but quenching is usual. As you say, it is a lot quicker.

Colin Bignell

[Matty F]

before. The brass came out of the

Actually this is the spinning tool!:

[fred]

Ta for the offer or more pics next time, it'd be nice to see how the shaping progresses during the process.

[Matty F]

Yes that has been my style in the past, carving things out of big blocks. But the original was made from sheet brass and I wanted it to match. Besides we don't have brass rod that big, and since the job was for another department we couldn't jusify buying brass in. And I wanted to try my hand at spinning. I'd like to make some headlamp reflectors about a foot wide out of aluminium.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Matty F saying something like:

[MattyF]

replying to Matty F, MattyF wrote: The lid on the right dates from about 1921. The new one has now tarnished and looks the same as the old one.

[John Rumm]

Gosh, not often a 9 year old thread gets revived, on topic, and by the original poster. You have been gone a while Matty, nice to see you back!

[Andy Burns]

Likewise, though I suspect many regulars have blocked homeownershub :-(