One of the most important requirements is disc blade concavity, that is, correct concavity. Further along we set forth the purposes of disc concavity. We feel it is important enough to devote the extra time and words in a discussion of the subject, because seldom is disc concavity talked about, and very few know that there is difference enough to cause good and bad work.
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 would have cost at least $300.
Small to mid-sized disc-harrows are a most useful tillage implement. Some farmers consider them indispensable. Discs such as the McD 10-A may be used with either tractors or big hitches of work horses. This tool will cut both plowed and unplowed ground. Ahead of the moldboard plow, the disc harrow is a valuable tool to cut up and free tough sod. When employed in tandem with spring tooth harrows, a great deal of work can be accomplished in much less time.
For best results, the draft angles (front frame) on the front harrow should be approximately level when the harrow is hitched to the tractor. If necessary, adjust tractor draw bar to obtain this result. In practically all field work the gangs should run level and cut at an even depth. Adjust the front harrow gangs to suit by raising or lowering the pressure plate at center of front harrow frame. The rear gangs may be leveled by raising or lowering the outer draw bar pressure plates. If the harrow ridges the soil between the rear gangs, the soil may be leveled by raising the inner end of the gangs, or by giving them less angle by moving the rear harrow frame forward at the three holes in the inner draw bars.
The true ‘Jackson Fork’ is arguably the single most iconic product invented by Byron Jackson, of early 1900’s San Francisco – but it was by no means the only important innovation/product Jackson engineered. As these old cuts testify, he designed many devices and systems for forage handling. Some, like the Threshing Outfits, were geared for handling large volumes of grain crop.
Within true horse-power circles, where natural partnerships with working animals are embraced and cherished, the family unit is paramount. Tools are being designed today so that a husband and wife with two to four work animals can see their work done. Scale is a defining aspect, going forward and backward. It is liberating and it is enlivening. Elegant even. And for us, we see the evidence both from afar and up close. Now to focus on what 25 years has taught us.
Cultivators are now so varied and improving every year, that it is hard to say that any particular one is the best. There are many patterns more or less valuable. My rule in all such things, when purchasing at an implement or a seed warehouse, is to ask what tool is in largest demand for a certain purpose, and I usually find that the public in the long run finds out which is the best article, and that the article most in demand is the one usually having the most merit.