Fast, affordable heating & A/C service.
Serving North Pinellas County.
www.ricksstrangeworld.com
Home Metal Casting
and Machining
Page 1
WARNING! Activities on these pages about foundry work are very dangerous. The chances of having a fire, causing injuries, or even dying are very good if you are not careful. I am not a professional foundryman, and will not attempt to disclose all hazards. If you choose to try this hobby, every precaution must be taken to be safe.
Sometime in 2004 I was surfing the internet and came across a series of books on how to make your own precision machine shop from scrap written by a guy named Dave Gingery. You melt down a bunch of aluminum scrap whatever in a small charcoal foundry you build and using basic hand tools you turn castings you made from the scrap into a complete machine shop of tools accurate to one one-thousandth of an inch! The books are numbered so as you build each machine it helps to build the next machine in the series. The lathe actually helps to build itself before it is even complete. The books are #1 Charcoal foundry, #2 Metal Lathe, #3 Metal Shaper, #4 Milling Machine, #5 Drill Press, #6 Dividing Head and Deluxe Accessories, #7 Sheet metal Brake. He has other project books as well. I figured if you could build precision machine tools and running engines from scratch, you could build anything! Melting down a bunch of junk and making it into something cool, this I had to try!
I
bought book #1 as well as the rest of the series but instead of building
Gingery's charcoal furnace, I built a coffee can furnace and used
a vegetable can for a crucible to see if it would work. Charcoal was
the fuel and a vacuum cleaner was the blower. Some strips of aluminum were
the melt. Air was blown in the bottom through a bunch of small holes
I punched in the coffee can.
Yep it worked. I made a
molten aluminum blob! But more importantly I discovered that it
worked! Charcoal would definitely melt aluminum. Those vegetable
cans do burn through often though. You might get one melt from them
before they spring a leak or crumble as you remove them from the furnace.
Molten aluminum at 1400 degrees is scary stuff and will vaporize human tissue if
it gets on you. The failure of even welded steel pipe crucibles is common,
never let any part of your body get under or near a melt . Also,
no water or moisture whatsoever should come into contact with molten metal or it
will explode, showering the surrounding area and possibly you with 1400 degree
molten metal. All it takes is a slightly damp tool or a drop of sweat
to cause an explosion.
The
charcoal worked but threw off a lot of sparks and ash. I wanted to improve
upon the melting safety and efficiency. I got lucky and found this used
electric mini kiln at a local ceramic shop. At 120 volts and 12 amps
I figure it cost me around 14 cents an hour to run. Added some welded
steel pipe crucibles and a sand box to melt and pour over and now melting aluminum is no longer a big event. After the first melt I also bought some Petrobond foundry sand instead
of making my own greensand for making sand molds. Greensand is cheaper but
going straight to Petrobond sand I eliminated the possibility of steam flaws in
the castings that some occasionally experience with greensand. To the left you can see
the molding flask for the lathe bed casting which had just been poured.
Since the lathe bed was such a long casting it required a special flask be made
just for it.
I
bought a Sherline mini lathe and mini mill to try machining and machining the
castings I was now making. Up to this point I had never used either a
lathe or a mill. The cast aluminum machines well!
I have completed my first Gingery project, the Haynes Hot Air Engine. It is
a Stirling cycle engine and yes it does run. The base, flywheel and
transfer piston were made out of "Scubonium" (an old scuba tank I
melted down and cast). The power piston was made out of "Canite"
(melted down beer and soda cans). Stirling engines are externally fueled
so they will run off of anything, they just need heat. I run mine with one
of those Bernzomatic propane torches people use to solder plumbing with.
In my Alternative Energy section there is a link to a solar powered Stirling
engine for power generation. Stirling engines were patented around 200
years ago.
The Gingery Lathe Project
The Gingery lathe has a few castings that
require almost a quart of molten aluminum. Up until that point I had not
done a melt anywhere near that kind of volume. The steel pipe crucibles I
was now using could maybe hold a third of that. So I bought some 5 inch
schedule 40 steel pipe and some steel plate for the bottom. I also made this pouring shank so I
could keep my distance from the molten metal. Now I am in business!
First try on the lathe bed casting.
It is hollow at the bottom with structural ribs . I
didn't let the metal superheat long enough and it froze in the mold before it
filled completely. This casting requires almost a full quart of molten
aluminum.
Got it on the second try. This is
probably the most difficult casting in the project and it was great
encouragement for me when I did it.
Here are some of the other castings for the project and you can see the wood
molding patterns I have made behind them. Sometimes the castings come out
pretty rough. When you are not happy with how a casting came out,
you just melt it back down and pour it again.
Here I am about a million man hours later. Getting ready to bore the
permanent headstock. A temporary headstock and a boring bar are made and I
am going to drive the permanent headstock into the boring bar to enlarge holes
in it for bushings. This is where the lathe starts to build
itself.
The
tailstock base is done and the form for the tailstock casting is
finished. Once the tailstock is cast and mounted, it will be driven into
the boring bar that is installed in the headstock until the thru hole is the
proper diameter. That is how the tailstock stays in perfect alignment with
the headstock.
All done but the base needs something.
Sanded and threw some stain and
clear on the old base and it came out pretty good. My Gingery Lathe is
done.
Home Metal Casting and Machining Page 2
Fast, affordable heating & A/C service.
Serving North Pinellas County.
