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How to Make a Rock Classifier

Rock classifiers utilize screens of various sizes to "classify" rocks according to their diameter. The screen hole size restricts rocks of larger sizes from passing through. Progressively smaller rock classifiers can be used to sort rocks by sizes. Optimal results are obtained when the classifier is suspended in water to allow small particles to be washed from the rock's surface. When the screen is lifted from the water, the rocks remaining are larger than the screen size. Classifiers are utilized by collectors and prospectors to reduce the total work required to recover ore.

Things You'll Need

Tape measure
Marker
Two 5-Gallon buckets
Hand saw
Spring Clamps
34 inches of 3/4-inch by 1/8-inch aluminum strap
Electric drill
5/16-inch drill bit
16-inch circular sheet of hardware cloth with mesh size of choice
Tin snips
Eight 1/4-inch bolts measuring 3/4 inches long
Eight fender washers
Eight wing nuts to fit the 1/4-inch bolts

Instructions

Preparation
- 1
  Draw a line on the outside of the bucket with the marker, 6 to 7 inches from the top.
- 2
  Saw the bucket along the line to separate the top from the bottom. Set the bottom of the bucket aside.
- 3
  Insert the aluminum strapping about 4 inches below the top part of the bucket. Form a ring along the inside edge of the bucket. Secure it in place with the spring clamps. Draw three unevenly spaced lines across the strapping onto the bucket to enable you to replace the strapping later.
- 4
  Drill eight holes through the strapping and bucket making sure at least one of the holes is drilled through the overlapped portion of the aluminum strapping to hold it in place when the bolts are secured.
- 5
  Lay the bucket top on the ground with the cut edge exposed. Lay the 16-inch circle of hardware cloth over the cut portion of the bucket and evenly align it. Draw a circle over the hardware cloth where it meets the plastic bucket. Place the hardware cloth on the ground, marker side up, and place the bucket top directly on the marked circle
- 6
  Use the tin snips to make 10 evenly spaced cuts toward the center of the hardware cloth, stopping at the marked circle. Fold up the hardware cloth along the outside of the bucket and press the metal strips along the marker edge to bend them in place.
Assembly
- 7
  Separate the bucket top and the hardware cloth. Place the bucket top on the ground, with the cut side facing down.
- 8
  Insert the dish-shaped hardware cloth into the top of the bucket and push it downward to the ground. Do not push the cloth so far that the top of the hardware folds are pressed below the aluminum band line, indicated by the three gaps in the unevenly spaced marker lines previously drawn across the strip.
- 9
  Insert the aluminum strapping along the inside edge of the hardware cloth and press it against the hardware cloth and bucket along the guide marks previously drawn.
- 10
  Insert the bolts into each of the eight holes drilled into the aluminum strapping, from the inside of the bucket outward. Adjust the hardware cloth or press the bolt through the screen, if necessary. Attach a fender washer and wing nut to each of the bolts on the outside edge of the bucket.
- 11
  Fill the second 5-gallon bucket with water. Lower the rock classification bucket top into the water-filled bucket. Place rocks or dirt onto the screen and agitate the bucket top to classify.

Rock Collecting