With more deer plots being added to the homestead, I decided it was time to pick up a disc harrow. While I have used a 5' rotary tiller behind my Massey Ferguson 1529, it isn't really crazy about rocks. Although not inundated with large rocks, there are more than enough football and baseball sized rocks that beat on the rotary tiller way too much. I'd rather keep the rotary tiller in good condition to use on the garden and also the garden's of a couple of neighbors.
I've been watching the local paper and the online listings for a small disc but finding a used one is nearly impossible in this area. Lots of folks have food plots wildlife and if a small implement becomes available, a friend or neighbor will buy it long before it ever makes it to the For Sale listings. The local fleet supply store carries King Kutter brand but the models they currently have in the 60" size were all angle iron frames. Thank you but no....I'm not buying a twisty frame disc that is too light weight to do the job. After talking to a neighbor, I called an implement shop to see if they had something available. Yes they did and they had two made by Bush Hog. I got some details over the phone and decided to take a look at them the following day.
The two available Bush Hog disc harrows they had on the lot were both 100 series models, the 1D60 and 1D78. The 1D60 is a 60" wide unit and the 1D78 is a 78" wide unit. I was quite sure that the 60" was all my tractor could handle and after talking with guy at the implement shop, he agreed with my decision. According to one of the online tractor forums I routinely visit, the rule of thumb is 5 horsepower for ever foot of disc. That would put the 1D60 at 30 HP and my tractor is rated at 28 HP. The owner's manual for the 1D60 suggests 35 HP.
As I mentioned, the Bush Hog has a tubular frame which is much stronger than the less expensive models using an angle iron frame. The tubular frame is also heavier than the same width angle iron frame disc. The common consensus is that you need approximately 40 pounds or more, per disc blade, to ensure proper tillage from a disc harrow. Less than this and the disc blades will not cut down into the ground and properly mix the dirt. According to the spec sheet for the 1D60, the approximate weight load is 35 to 38 pounds per disc blade. In contrast to this, the 1D78 is 30 to 32 pounds per disc blade. You might initially think that a "bigger" disc would put more weight on each disc blade, but it doesn't. Why? According to the spec sheet, same size tubular frame is used on both models. So the 78" wide model has just a little more weight due to the axle and disc blades but that is not enough to compensate for the number of additional disc blades that is distributing the weight. All things being equal, I should see better tillage performance from the narrower 60" disc harrow. I would have to jump to the 200 series model in order to see a heavier frame and more weight per disc blade.
The bearing hangers connect the axle to the gang tubes. In the above photo, you can see the gusset that reinforces the bearing hanger. Nyloc nuts hold the two large U-bolts at each bearing hanger where the fit over the tubes. Each axle is connected in this fashion with a pair of these hangers.
Here is a better view of the U-bolts and bearing hangers on one side of the front axle. This makes for two bearings per gang and a total of 8 bearings on the disc harrow.
The one thing I noticed and was not overly impressed with was the sealed
bearings that are used. I like the moving parts on my implements to have
grease fittings. I don't have a problem spending a few minutes greasing
the implement prior to use. I grew up on a farm years ago and everything
was maintained in this fashion. I hope that these bearings are truly
sealed and that nothing can get into them and cause premature wear.
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