Senior Apprenticeship: Herreshoff Steam Engine Casting
A team of 9 senior Mechanical Engineering students set out to finish casting a replica of HMCo's TB-15 pumping engine for the MIT Museum.
I generated G-code, milled molds, and cast the lower bearing on the eccentric rod. (boxed in red below.)
I generated G-code, milled molds, and cast the lower bearing on the eccentric rod. (boxed in red below.)
Milling Molds
G-code was generated in MasterCAM. The parting line is vertically centered on the bearing and the bearing is symmetric. The molds were made out of foam. This mold produces two bearings. (Only one is needed for the engine.)
There is a simple hole in the bearing so the core is just a cylinder. The mold above has extended cylinders on both ends to locate the cores.
Packing
The most physically demanding part: packing the flask.
Pouring
The bearing was made out of Silicon Bronze (873). The material was heated up in an oven and then poured into the mold.
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Potato
After waiting a day or two for the 873 to cool, the potato is broken out.
The second pour was successful.
Machining
The runners and risers were cut off on the bandsaw and then the part was milled to specs.
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Final Product
The exhibit at the MIT Museum, Lighter,Stronger, Faster: The Herreshoff Legacy, opened October 2018 and will continue through May 2021.
Technical Skills: MasterCAM, casting, mill, bandsaw, process design