How to Build a Small Stamp Mill
Stamp mills are used primarily to crush ore in mining operations, though they are sometimes used to pulp softer materials, such as seeds for oil and fibers for paper-making. The key components of a stamp mill are the mortar, or holding container, and the stamp, a weighted post that drops from above to pulverize the raw material. Historically, large mills of 20 or more heavy stamps were constructed next to rivers and powered by waterwheels. But if you can weld, you can build a manual portable single-stamp mill that fits in the trunk of your car for rock-hounding or hobby prospecting.
Things You'll Need
- Welding gloves
- Welding goggles or helmet
- Arc welding kit
- Steel or iron pipe, 2-inch inner diameter, 1/4-inch thick, 16 inches long
- Steel or iron plate, 1/4-inch thick, at least 8 inches square
- Solid steel or iron rod, 1 1/4-inch diameter, 3 feet long
- Steel or iron pipe, 1 1/4-inch inner diameter, 1/4-inch think, 1 foot long
Instructions
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Construction
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1
Put on the protective gloves and welding goggles or helmet. Make sure you are wearing protective clothing that does not expose your skin, such as long pants and a heavy long-sleeved jacket.
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2
Clean any dust, rust, paint, oil or water from the ends of the pipes and rod and from the surfaces of the plate.
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3
Set up the arc welding equipment with the appropriate electrode.
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4
Weld one end of the 2-inch pipe to the center of the plate. This will be the mill's mortar.
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5
Weld one end of the rod to one end of the foot-long piece of pipe or rod. This will be the mill's stamp.
Operation
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6
Place the mortar on hard, solid ground, with the open end of the pipe facing up.
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7
Place the material you want to crush in the mortar and slide the narrow end of the stamp into the pipe.
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8
Stand with one foot on the plate of the mortar, lift the stamp about 1 foot up within the mortar's pipe, and let it drop. Repeat until the material is crushed to the desired consistency.
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1
Tips & Warnings
You can make your mill larger by using a larger diameter pipe and rod. Just make sure that the rod fits easily into the pipe and that it is not too heavy to lift.
You can mechanize your mill by adding a camshaft system powered by an electric motor. In this case, you will probably also want to affix the mortar to a secure, weighted base, by setting it in concrete, for example, which will make the equipment less portable.
Arc welding is a skilled technique that requires some experience and caution. It can be extremely dangerous if not done correctly. Do not try it without the proper instruction, equipment and protective gear. Make sure all your skin is covered and wear eye protection specifically made for welding to avoid UV flash from the process.
Weld in a well-ventilated area, as the fumes from arc welding are toxic.
References
Resources
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