This is a link to a video about making a Japanese sword guard by a superlative metalsmith called Ford Hallam……entitled; "the search for Katsohiro's tiger"…….It's well worth watching by anyone who makes stuff in metal whatever the discipline or purpose…

In the video he casts a disc of copper and silver alloy and then beats the disk using hammer and small anvil…..you should watch that part of the video as it will tell you exactly how to do wha tyou want to do.

If you soften (anneal) the brass it should be easy to squeeze out a 50mm disc to over 53mm, using a hydraulic jack, for example.

Tim

Edited By Tim Stevens on 09/07/2019 23:12:42

Find someone with a BIG fly press. You would want to give it one big thump as it will quickly work harden.

Edited By Speedy Builder5 on 10/07/2019 06:30:03

Life's to short and the gas will cost near as much as an offcut. I would just buy a piece. I often see small offcuts at the motorcycle autojumbles and shows, I will check my stock I may even have a piece, where are you ?

I can echo the words of others on this one after my experience in making car radiator top and bottom tanks from brass sheet.

I had done some google searches and read the books but even so the best advice came from a particularly skilled and experienced engineer who was aware of the pitfalls of the wrong grade of brass and the limitations of the home workshop. My first attempts were pitiful but with his advice I succeeded.

Beware overheating the brass , when it goes crystalline it is scrap.

I was shown to use soap rubbed onto the surface and heat until the soap turns brown.

My (sadly now deceased) friend's advice was to press or draw the material if possible as hammering work hardens it so quickly.

Do not be put off from having a go – actually trying it is part of the fun and adds to your knowledge and skills.

Posting your question here helps others like me to learn also.

I never cease to be amazed at the breadth and depth of skills and knowledge held by members and so generously shared with fellow enthusiasts.

Edited By John Paton 1 on 10/07/2019 09:19:35

Turn it. If the turnings come off as a spray, go to Metals4u and save the planet from greenhouse gases.

Regards Ian

Edited By Circlip on 10/07/2019 11:03:14

Andrew, I have looked at my stock and have nothing over 2" for you. The 2" piece I found is about 3 1/2" long and has still got the price on in felt pen. £3 I usually pick up useful bits and bobs from the bike shows. Chris.

I find the Workshop Practice Series excellent for questions like this. № 30 is 'Workshop Materials' and it has much to say about Brass, buy the book! Edited highlights:

• Much depends on the type of Brass. Some alloys are better suited to hot working than others. In addition to different alloys being available, brass is sold in 'soft', 'quarter', 'half' or 'fully' hard condition. (Soft brass could be hammered usefully first without heating, hard brass cannot.)
• In the book only Naval Brass and the very similar Muntz Metal are associated with hot forging.
• It is easy to overheat brass, 400-600℃ (dull red in subdued daylight) for a short time is enough to anneal it. Overheating weakens the metal, which may be a concern if the strength of the new disk is critical. (So does beating hard brass, because it's brittle.)
• Being copper based, brass absorbs a lot of heat, ie relatively expensive to get up to temperature compared with steel.

Comment:

The book implies to me that most Brass is worked carefully cold or hot rather than forged to avoid damaging the metal. The most usual approach is to soften the brass by annealing, then hammer cold or as it cools down until it work hardens, then repeat annealing until the job is done.

I suspect Brass can't be beaten into shape like Iron or Steel simply by hitting hot plastic metal with a big hammer. Softening by annealing is a more subtle technique, but it might be easier to do in a home workshop lacking a forge. My guess is that the brass alloy used to make, say, plumbing parts is much easier to damage by overheating and work hardening than the type used for electrical components, while both are inferior to Naval Brass, with Naval Brass being markedly harder to forge than steel.

So I'd try the annealing method. Please let us know what happens whatever you try!

Dave