I was considering aluminum because of the cost. As long as I maintain alignment, the saw blade shouldn't present any issues. I could also try getting it made using a LASER sintering 3D printer, which would eliminate the tooling issues. In the final product it may also be possible to eliminate the centre fins, as they're an experiment in trying to limit the amount of blow-by that the cutting oil might experience, during operation.That looks light a nightmare to machine using conventional tooling (probably easier to make as left/right and then attach together). Luckily, at least one gtamer seems to have access to a wire Edm that could bang it out easily. If I have the operation right in my head, hardened tool steel would be a better choice than aluminum as the saw will open up the slot in the aluminum.
I also banged this out, over the past couple of weeks, for a friend who wrote the "Airship Daedalus" series of Dieselpunk novels.