You might look at the site below for ideas. Looks like you could use a steel shoe with brass or bronze sides, and dovetail the two together given that you have a mill. The other alternative is to have the body cast at a foundry, you could design the body maybe with a 3D printer? Years ago when I was building boats I fabricated molds that we sent to foundries to cast bronze healing bearings for the rudder, and other parts. Was fun to see the process and the end result. There are some posting of individuals casting iron planes, but need to get the correct metallurgy. Some of the plane parts are available the online vendors like Woodcraft. I have an assortment of planes from many decades ago, my go to plane is still a Japanese hardwood pull type (same as the Kanna) that must be 50+ years old.
http://sauerandsteiner.blogspot.com/
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