A rotary trommel sifts dirt and debris. Landscapers use the device to separate large chunks of earth from smaller rocks. Gold and rock hunters use the device to sift out smaller pieces of stone. The dirt rotates in the drum of the trommel, breaking larger chunks into smaller pieces. Screens placed on the side of the trommel allow smaller pieces to fall through the mesh. Trommels are available in different sizes, from 55-gallon drums to smaller affairs, and can be rotated by hand, or attached to a small motor by means of a pulley.
Measure the diameter of the barrel. Purchase two bicycle rims that are the same diameter as the barrel. Lay the barrel on its side and attach a bicycle rim to either end of the barrel.
Remove either the top or bottom of the barrel. Wearing safety goggles, drill through the bicycle rim and barrel. Push a small bolt through the hole and secure it with the nut inside the barrel. Repeat every 2 inches around both bicycle rims.
Drill a hole in the side of the barrel. Using the hole as a starting point, cut a 1x2-foot hole in the side of the barrel. Repeat on the other side of the barrel. Cut the wire mesh in half so you have two pieces measuring 1 1/2 feet wide and 2 1/2 feet long. Reach inside the barrel and place a piece of mesh over a hole with several inches of overlap on each side. Secure the mesh with the staple gun. Repeat with the other side.
Measure the width of the bicycle rims on the barrel. Purchase casters that fit inside the rims. Measure the distance between the bicycle rims on the barrel. Screw the casters to the wooden table so that they correspond to the width of the rims. Screw two casters on either side of the table close enough that the barrel will rest on the casters and not touch the table.
Find the exact centre of the bottom of the barrel. Drill a hole and insert the screw for the crank assembly. The crank can be whatever size works best for you and your size barrel. Cranks are available at any local hardware store from small window cranks to larger patio and awning cranks. Attach the crank to the other side of the bottom. Secure the bottom of the barrel to the barrel with the staple gun.
Cut a 2x2-foot hole in the wooden table between the casters. Lay your barrel assembly on top of the casters.
Fill the trommel with dirt through the top of the barrel. Secure the lid. Rotate the barrel by turning the crank clockwise.
You can add a flywheel to the bottom of your barrel and rotate the trommel with a dryer motor, but these motors tend to go faster than expected and will spew dirt by means of centrifugal force. Play with the speed of any motor before attaching it to your trommel.
Always use protective eye wear when using a trommel. Dirt, stone and debris can fly in all directions.