Ted and tbuelna, thank you so much for your replies so far. I have 8 different gears, all in the same general size range, and I plan to have 100 pieces of each made if I can make the costs work. I'm not sure if they'd do 3D printer for that quantity, or if they would force me into aluminum...
hydtools,
Looking up Ductile iron for investment cast in machinery handbook it shows Ferritic and Pearlitic. It does not give specific numbers like you mention. What do each of those numbers represent?
The Ferritic is list as 143-200 Bhn, which is roughly Rc 0-13 ish. So perhaps that was...
tbuelna, I have tried to reproduce these gears by taking my best set and filling pits and such, and spraying with shellac. Then I had the caster use them directly in the sand mold. The parts came out with finish too coarse, too much flash and voids. I don't know of anyone using a finer grade...
I'm working to reproduce an old bevel gear set that was originally sand cast and secondary machined. They were originally an iron gear and were quite soft. I had someone hardness test them and they came out to about a HRC 2. They are slow speed gears that are actually turned by a crank. I...
