by Justin Reynolds of Glouster, Ohio
This is the story of a harrow on a budget. I saw plans on the Tillers International website for building an adjustable spike tooth harrow. I modified the plans somewhat to suit the materials I had available and built a functional farm tool for eighteen dollars. The manufactured equivalent, a metal three foot spike tooth harrow, would have cost at least $300.
The original Tillers design calls for a combination of wood and metal materials. I used wood for some of the pieces they had called for to be metal because that’s what I had available. The wood I used is oak I had on hand from a dismantled barn and the spikes are eight inch pole barn spikes which I purchased new. I originally scrapped together the nuts, bolts and washers which connect the moving parts but I ended up just buying some so it would be uniform and more functional. The bottom of the runners have a strip of metal for added durability.
I began the project by working on the runners. I used two pieces 1-3/4” x 4-1/2” x 63” and a half inch paddle bit to drill holes 10” apart, centered on the 4-1/2” side, starting 13” from the front. I rounded off the front of the runners with a chainsaw.
Next I created what we’ll call the cross members. They are made from five pieces 1-3/4” x 2-1/4” x 46”. Then, 2” from each end I used a table saw with the blade set about 1/2” high to make a cut on all sides. After that I used a mallet and chisel to make the ends rounded to fit into the holes in the runners. Finally, I drilled holes 10” apart into the 1-3/4” side starting 6” from one end to put the spikes into. I was careful to drill the holes slightly smaller than the spikes, so they would stay in place but not so small that the wood would crack as I pounded them in.
My next step was to fit the cross members with spikes into the runners. Cross members next to each other are reversed so the spikes are offset. Then, I screwed one 1-1/2” x 3-1/2” x 46” piece at the front and back of the runners on the top, to hold them together.
Then, I began to assemble the moving adjustable parts. There are five pieces of 1-1/2” x 1-1/2” that I screwed in the center at a right angle on the 2-1/4” side of each cross member. The front four are 16-1/2” long and the rear one is 42” long and serves as a handle. We’ll call these the vertical members. Once these were attached I drilled 3/8” holes 2-1/2” from the top of each vertical member going left to right as the harrow sits.
Next, I used a piece 1-1/2” x 2-1/2” x 43-1/2” that we’ll call the horizontal member and drilled 3/8” holes every 10” centered on the 2-1/2” side, starting about 2” from one end. Then, I attached the horizontal member to the right side (when viewing from the rear) of the vertical members using 4” bolts with lock nuts. I put washers on each end of the bolt and also in between the horizontal and vertical members. Now all the cross members rotated in unison by moving the rear vertical member. When in use this allows the angle that the spikes contact the ground to be adjusted to the desired level of aggressiveness. The spikes can also lay almost parallel to the ground when transporting the harrow to the field.