Brass Standards

Brass is an alloy of copper and zinc, but often other elements such as aluminium, iron, manganese, tin and lead are added.

There are two basic classes of brass:

  1. Alpha alloys – less than 37% zinc – ductile and can be cold worked.
  2. alpha/beta or duplex alloys – 37-45% zinc – have limited cold ductility and are harder and stronger.

Note: the brass gears were cut using the Hobbymat MD65 and were made for the Solenoid v-Twin.

British Standards:

  • CZ101
  • CZ108 Brass – A common, high purity brass alloy suited to many general applications and often used used in general electrical engineering (sheet/strip products). Hardness and strength are both excellent and this alloy is well suited to cold forming.
  • CZ112 Naval Brass – added tin gives better corrosion resistance.
  • CZ116 Higher Tensile Brass
  • CZ121 Free Machining Brass – cold working is poor.
  • CZ126 Arsenical Brass – increased resistance to corrosion. Its ductility and strength is better than other common alloys.
  • CZ131 Turning and Riveting Brass

Other Descriptions:

  • Yellow brass – An American term for 67/33 or 65/35 brass.

Machining Brass

When machining brass in the lathe or milling machine I tend to work dry and don’t use any form of cutting oil. For the lathe tools I use a very shallow tool.

Finishing Brass

If you want a very bright finish then use a very fine wet and dry paper and then finish with wire wool. Note that brass tarnishes quite quickly and so you will either have to buff regularly or use a lacquer.

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