I’ve done my research, I’m pretty sure I know the answer, but its worth the question: Has anyone carved/engraved cast iron with your Shapeoko? If so, tips, bits?
How deeply do you need to engrave? How large an area? Would a diamond drag engraver be an option?
What do you mean by “carving”?
I wpuld like to make something like this picture. I’m willing to purchase the bits I need, I’m just looking for direction and experience. I have only cut (a lot) of wood and pvc with my Shapeoko (Dewalt router).
Not sure the shapeoko would be the best tool . Cast iron is very hard, brittle and requires thick shanked carbide tooling. You’ll need flood cooling and chip removal, but most of all, the need for absolute rigidity is a must. The speed of the router will also be an issue as likely may be too fast and the touque imposed could eat the cutters quickly, I’m thinking a cnc mill would be a better choice and running software instructions . Tom
Regardless of the stock material chosen, a DDE bit will not do more than scratch the surface. With a few passes you may reach a depth of 0.2mm (almost 0.008") but that would be a big ask in cast iron. And you wont get the sculpted depth or width of the alpha-numeric characters.
Your machine would need to be well fettled and rock solid (as per @Rxman) The cooling a chip removal adds a layer of complication. You may be able to buy cutters that have 3/8" shanks and the necessary 3/8" collet that will fit your router providing it is a Makita or Carbide 3D router. The cutters will need to be for steel.
Possibly you may find it more expedient and cheaper to design what you want and hand it off to a company that has the machinery to do what you want. I have only recently been cutting aluminium on my machine, after giving it a massive rigidity upgrade. While I may try tackling steel (I have a new project to cut some stainless steel) soon, I would not expect to be able to carve cast iron.