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bright idea Pattern kits for Gingery machines?

So here’s a random idea I had.

Most readers are probably familiar with Dave Gingery’s series of books on building a set of homemade machine tools. The technique, basically, involves building an inexpensive homemade charcoal furnace and crucible for melting aluminum, then using traditional green-sand casting techniques to mold the various machine parts from wooden patterns. Much of the content of Gingery’s books details the construction of these patterns.

As I have recently discovered, however, lost-foam casting is a much more accessible metal-casting technique than traditional green-sand. It requires no special flasks, no special sand, and no consideration of parting-line placement in designing patterns. Basically you make your pattern from styrofoam, bury it in sand, and pour hot aluminum into it. The foam vaporizes and diffuses into the sand, and you’re left with a perfect aluminum duplicate. The only downside is that the pattern itself is destroyed, so if you screw up the casting or want more than one copy of a part you need a new pattern.

Here’s what I’d like to see: Some enterprising soul with a CNC foam cutter could sell kits of the Gingery machine patterns ready-cut in XPS foam.

Then, if you wanted to build the Gingery tools, you wouldn’t have to spend a lot of time learning the art of green-sand casting, or building the special tools required, or carpentering on the patterns themselves, most of which will only be used once anyway. You’d just buy a few ounces of pre-cut foam patterns in a kit, bury them in sand, and start pouring hot aluminum right away. Depending on sales volume, it might even be practical to make the foam patterns in conventional molds, the same way styrofoam packaging inserts are produced, at lower cost than CNC machining.

If you’re interested, supportive, or (for your own unfathomable reasons) furious, feel free to sound off in the comments.

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c’t – Magazin für Computertechnik, and The Wall Street Journal.

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