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Center Cut Mower

Center Cut Mower

Center Cut Mower

article and photos by Ben Jahnes of Hopewell, OH

Necessity is the mother of invention, as they say, and old used things aren’t necessarily cliché. That was my epiphany when I ended my search for a center-cut horse-drawn sickle-mower.

My foray into animal-powered agriculture began with a bred heifer and a bit of sentimentality. You see, my first calf ever was a bull, and who wants to send their first calf to the butcher? The solution to this dilema was a bit of education, on both my part and the bull’s, and a yoke. I was on my way to training an ox.

With ox-power on the horizon, I began looking for tasks on the farm suitable for animal power, and one of the most attractive seemed to be mowing. I caught sight of a couple of youtube videos featuring horse powered haymowers, and I was mesmerized by the pleasing hypnotic song of the sickle-bar mower, clipping through the grass to the hoof-beat of biological power. The desire to play this song, myself, led me to purchase an old rusty John Deere mower, and Lynn Miller’s Horse-Drawn Mower book. I learned that, with some work, my new-old mower could cut grass with more elegance than any modern fossil-fuel-powered appliance.

The prospect of clipping pastures and cutting hay with the mower was satisfying, but I wondered how I might take advantage of a sickle mower in my primary crop of grapes. The problem is, my grape rows are about 9 feet apart, and the haymower is well over 10 feet wide. The Horse-Drawn Mower book hinted at the solution; the center-cut haymower, but an internet search quickly proved the obscurity of such machines, and an antique center-cut mower would be hard to find. Surely there must be existing technologies to address my situation. Hours of searching revealed a prototype center-cut mower on the opposite coast, in Oregon, or the slim possibility of adapting a motorized walk-behind mower to ground-drive. With the prospect of lots of trial and error in assembling something nearly from scratch, I decided to reexamine the past, as many of us do in our unconventional agricultural pursuits.

The John Deere and McCormick Deering mowers have served us well through the decades, and proved their durability. Is it possible to adapt this proven technology rather than tinker with untested modern stand-ins? A couple of mental models and a sketch were enough to decide it was worth a try. With a second mower to experiment with, I set off with the task of reversing the bar and guards to lay across the front path of the machine’s wheels. The following is a detailed documentation of how the conversion was completed.

Center Cut Mower

The existing mower bar was stripped bare of guards, hold-downs, wear-plates, and removed from the inner and outer shoe. When flipped over and reversed to the left direction and positioned to be re-bolted to the inner shoe one notices that the underside of the mower bar has a raised rib towards the rear edge. This rib has a corresponding groove in the inner shoe that is left empty when the the bar is flipped.

Center Cut Mower

To ensure stability of the bar when bolted on upside-down, a shim is cut from bar-stock to fill the gap.

Center Cut Mower

Extending the shim to include a false guard will multiply the cutting surface of the inner ledger, as plugging might occur with the short inner ledger plate on the John Deere.

Center Cut Mower

When the inner shoe wear-plate is placed on the bar for re-installation, one notices that the rib will not allow the wear-plate to sit flat, so a sliver must be cut off of the back side to allow it to be seated properly. A thin shim must be sandwiched over the wear-plate so that the knife-head guide will be level.

Center Cut Mower

A reversed knife must be made to operate on the reversed cutter-bar. Any knife can be converted by removing the knife-head from one side of the bar, and riveting it to the opposite side of the knife, in a backward direction. For the knife to fit in the knife head guide, about 1/2” must be removed from back side of the head using a cutoff blade.

Center Cut Mower

A thinner knife-head guide must be fabricated to allow the pitman to attach properly and reciprocate unimpeded. The bar must be re-bolted to the shoe with a smaller nut on the right stud so that that the pitman head doesn’t rub.

Center Cut Mower

With the guards and hold-downs reinstalled on the bar, a small 2” caster wheel can be bolted onto the far end of the cutter-bar where the outer shoe holes remain. The outer shoe cannot be reinstalled because the hole pattern is reversed when flipped. The cutter bar can now be pinned back on the mower yoke, and the bar’s lead can be adjusted. Lead on the center-cut mower is the opposite of that on the normal haymower. To align the knife slightly forward of the pitman, the elliptical yoke adjustment should be shifted clockwise to increase lead. With the cutter bar now under the mower, the mower pole must be supported so the mower frame does not rest on the cutter bar and bend it. With the Mower reassembled, one can mow in short grass, but long grass will be pushed forward by the timing bar and be sandwiched between the pitman and the cutter bar, causing clogs. To clear potential clogs, the pitman can be modified to rake the falling grass as it cuts.

Center Cut Mower

Tines are inserted into the bottom edge of the pitman every 3 inches along the length, and cut so that they are shorter approaching the head. With this complete, the center-cut mower will cut and windrow the grass to the left side of the machine.

The converted center-cut mower performs beautifully over even ground, operating in fairly tall grass. However, it must be noted that such a converted machine has limitations. Because of the placement of the cutter bar under the frame of the mower, there is reduced ability to raise the bar off of the ground to clear obstacles. Additionally, the caster wheel on the left side of the mower always rolls over the ground, even during transport, so attention must be paid to its path.

So what’s the point of a center-cut sickle mower… couldn’t I just use a trailing gas-powered rotary mower to mow my vineyard? For animal-power purists the center-cut horse drawn mower provides the satisfaction of mowing in tight rows with 100% animal power. People not put off by another engine to maintain might be satisfied by a trailing gas-powered rotary mower. In my application, the rotary mower won’t work because I have intentions beyond trimming grass. At Flint Ridge Vineyard we practice mow and mulch, or mow and throw mulching. This weed control practice consists of mowing grass and raking it under the grapevines to smother the undergrowth. When grass is cut with a rotary mower it is shredded so much that it is difficult to rake, and doesn’t create an even mulch. The grass cut by a sickle bar mower is long and coarse and can be raked like a hay windrow under the row of vines, effectively covering many of the weeds.

Center Cut Mower

The beauty of this center-cut mower is in the simplicity of the conversion, the minimal expense, and the adaptability of a machine that you might already own. With a little time your mower can be converted back and forth between haymower and center-cut mower, serving multiple uses. This is another situation where it isn’t necessary to reinvent the wheel, just tweak it a little.

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