I wanted to build myself a metal lathe, per David Gingery's Home Metalworking Shop series of books.
That involves casting a lot of parts out of aluminum.
To do that you need a foundary.
This one is based on the "Improved Little Bertha" created from plans found here Unfortunately just as I was finishing it up Rachel had a mishap & I really haven't had a chance to work on it since which is a pity as it's basically ready to go :(. Until I have a reason to get back to it here's what's what-
Doesn't look like much yet does it?
A look at the lower body with handles etc. mounted
Screen to hold in the refractory
Part of the top hoop showing the fingers to secure the mesh that holds the refractory in place
Top hoop complete with mesh in place. If I ever do this again I'll use perforated sheet metal instead.
Grooving the fire brick to hold the heater element.
The grooved bricks, notice the mitre on the edges so they'll form a nice hex shape. The center bottom brick is drilled for the electrical terminals.
The terminals to connect the heating element to- They're stainless bolts that I drilled & tapped the heads to accept 18x24 screws. >
The terminals installed in the brick. I welded on th "L"s to get them close enough to fit into a standard electrical box mounted to the outside of the lower body. I added a short piece of strapping to the center terminal to "grab" in the refratory so if (when) the bolt loosens it won't turn.
The Perlite & stove cement mixed up ready to get poured into the body.
The refractory poured into the space between the bricks & body. As I upsized this from the plans it took a LOT more refractory than I thought it would to fill.
Here the refractory has been cast into the body & top. The Kanthol heating wire is installed into the bricks & connected to the terminals which are accessed from the back. Once upon a time they made boxes with three knockouts in the back. apparently no more :(. Note the center terminal is not connected to power, basically it's just there to tie the two lengths of heating element togeather. Also note the 110V power cord, I ran it on 110 initially just to get it warm enough to dry out the refractory. When complete the unit runs on 220.
A look down into the Glory Hole.
There still needs to be a drain hole drilled through the bottom in case of a crucible leak, the grooving on the bottom bricks is to facilitate any leaking metal to get to the hole.
You can see the tip of a type K thermocouple element sticking in through the brick at the "top" side of the chamber. It exits through the back for connection to a pyrometer.
Speaking of the crucible, here it is all eager to get started :). This one's thick enough it should last for a while. I still need to form a spout & drill holes for the tongs to fit into.
Here's the whole thing together. It does look a little bit like the picture in the plans so I guess we can consider it a success so far-
Well that's it for now. Now that I've wimped out & bought a lathe instead of building one the primary requirement for the foundary is gone but I still want to finish it off & pour some metal, just looks like too much fun not to. Plus I wanted to build the Shaper too :).
Dan's Workshop, home of the Improved little Bertha & other good stuff-
Budget Casting, where to get all those little casting odds & ends
The Hobby Casting mail list on Yahoo, they've been there & done that
And the Gingery group
Comments? Questions? Spieling Erorrs?
Please feel free to contact me Here :)