Engraving aluminum on chinese 3040

[Zeeflyboy]

difficult to say what to use for your lettering without knowing what sort of style you are hoping to achieve and the type of text.

Carbide is always going to be a good idea where small and thin tools are required due to the high rigidity, but beyond that it's a bit difficult to answer your question.

For 3d relief I don't have much experience myself but I believe most tend to use a tapered ball nose, like these for example: https://www.toolstoday.com/p-6225-ba...uter-bits.aspx