Re: custom HT parts and 4 stroke mounts
Size limit is very big for investment casting, bigger than bike parts. My current furnace is small, will be building bigger soon. My weight limit is about 6 pounds for one part. Bigger furnace will hold a 20 lb capacity crucible.
For sand casting, I can make parts up to 5x11x11 or 9x7x5 depth by length by width.
My machinist has cnc. I have autodesk inventor pro and AutoCAD. I have no computer controlled machines or anything like that. I specialize in investment casting using foam that I cut and shape, much more versatile than traditional sand casting. It's good for one-offs. I do make two part sand molds, that's what is used for HT parts. Heads, covers, ect. I will make permanent patterns for my 4 stroke mount if I get more than say, 2 orders. That will drive the cost WAY down. The alloy I use for structural parts is 356. Its used very commonly in automotive parts and wheels, and I quench it for a T4 treatment. For decorative parts I use extruded scrap, it's usually 6061 or similar. Much easier to work with after casting. 356 casts like a dream, very liquid and low shrinkage and super strong which makes it hard to work.
I can work from rapid prototype parts. They can have no undercuts because the pattern must be pulled from the sand cleanly. It is good to have about a 1° angle on the sides to ensure it pulls out cleanly.
Native files? Surface files? I do have 3d design software as I mentioned.