Hi, Jason.
I think you have a very good plan.

I took up the hobby of metalworking in the early 1990s. Then in 2000
bought into an electronic assembly service. The hobby turned into a
necessity! Lots of machine repairs, tooling and fixtures to be made
and modified. Also am able to do some production machine work we would
have had to send out to local shops. Means the money stays right here!

You will find the cast iron used in sewing machines is the finest cast
iron ever made. I have salvaged several to use in projects and have
never found any voids or hard spots in the iron. Its nothing compared
to window sash weights! Many of the bearing surfaces are cast iron and
steel with a little oil for lubrication. I have only seen the personal
sewing machines, not the commercial type, but they can't be anything
but better quality.

The cast iron will produce a lot of dust, as mentioned, but no sharp
edged swarf. The dust is heavy and doesn't float in the air for long.

In all but a very few cases, I have used aluminum for fixturing. You
will need to find a ready source for aluminum and steel cutoffs. Check
with your local machine shops. I got most of mine at garage sales and
auction sales.

You will probably want to use carbide tooling.

Good luck with the projects!

Paul Drahn
Jodeco, Inc.
Redmond, OR