The most difficult part that I ever made in the investment process, was a generator housing for an old firetruck for a gentleman in Oklahoma.
I never did find out what the truck was, but the housing was the brush support end frame.
It also held the gear driven distributor, plus another drive off the rear end of it, possibly a tachometer.
The mold consisted of 14 internal pieces (inserts) to create the housing.
One picture shows a small boss for a small shaft.
The mold took 2 weeks to make as the old part had pieces falling off of it.
I had to JB Weld the parts back in and make up for what was missing.
I made 2 for the customer and one for me. I now have a similar generator housing to do for a gentleman in PA, but it is a little smaller.
Making this in wax involved only making it ready for wax. The next one will be very much more involved as I need to make the inserts out of plaster or urethane, then make a mold of each one of them so I can reproduce each one in NO-Bake sand .
Here are the pictures: