Draft Animal Equipment






Hitching a Sulky Plow

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A Pioneer sulky plow doing good work behind a three-abreast of Belgians. Photo by Sam Moore.
by Sam Moore
The satisfactory performance of a riding plow depends to a large degree on a proper hitch that takes into consideration the correct line of draft. An incorrect hitch on a riding plow isn’t as evident as on a walking model, since the wheels carry the unwanted up and- down or side forces that result from an incorrect hitch, and the operator doesn’t have to fight the plow handles. Heavy draft and a poor job of plowing, however, are the inevitable result of careless hitching with no regard to the line of draft.
Line of Draft
When plowing at average depth, a single bottom plow’s center of load is at the point where the center of the draft line hits the plow bottom. This point usually falls at the junction of the share and moldboard and inward a couple of inches from the landside. A straight line, beginning at this center of load, running through the plow hitch clevis, and then to the hame hooks, is the vertical line of draft. The center of load will be slightly higher on the moldboard for deep plowing, and somewhat lower on the share when plowing shallow.

A plow in the ground offers resistance to being moved forward. When the horses move forward, they apply force to try to move the resisting plow. The two opposing forces always cause the line of draft to try to straighten itself out.

Avoid the common tendency to hitch too high on a sulky plow. This upward break in the correct line of draft causes the front of the plow to be pulled down and the plow to bounce along on the point of the share, while the tail wheel or landside is waving in the air and the plow is weaving from side to side in the furrow. On the other hand, a too-low hitch lifts up on the front of the plow, making penetration difficult and putting horses, the point of hitch should be higher than when plowing shallow or using small horses. If horses are hitched strung out in tandem, the point of hitch must be lower than when the horses are hitched abreast.

This line of draft is one of the most important factors controlling a plow’s operation. If you hitch so as to keep the line of draft straight while the plow is working, the implement will do good work—as long as the other adjustments are correct and the share isn’t worn out—and the load on the team will be reduced.
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The red line represents the correct vertical line of draft for a sulky plow. Drawing by Sam Moore.
Vertical Hitch
Most sulky plows have a vertical clevis with several holes that allow the hitch to be raised or lowered. These adjustments, along with shortening or lengthening the traces, should allow you to attain the correct vertical line of draft no matter the size of your team. Shortening the trace chains straightens a too-high hitch, while lengthening the chains has the same effect on a too-low hitch.

A small team must be hitched to the plow at a lower point than a large team. Also, a close hitch requires a higher hitch point than one using longer traces. To attain the correct line of draft, a big team generally needs longer traces than a small team. A tandem team requires a lower hitching point as well.

One way to check for the correct hitch height is to stop the plow when it’s operating at the desired depth. Stand in front of, and between the furrow horse and the first land horse. Sight along the traces from the hame hook to a point representing the center of draft. The point of hitch at the plow clevis should be on your sight line.
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The effect of a too-high hitch on a sulky plow is exactly the same as on this walking plow.
Horizontal Hitch

Side draft is not as critical on a sulky plow as on a walking plow. Side draft results from having to move the hitch clevis toward the land from the plow’s true line of draft when using a three-abreast team, to allow the right horse (when using a right-hand plow, or the left horse on a lefthand plow) to walk in the furrow. This side draft causes the plow to try to run at an angle to the forward motion of the team. Excessive side draft causes increased wear on the plow, uneven furrows, and increased draft, although a certain amount of side draft is counteracted by the plow wheels and may be a good thing, as when plowing on hillsides where the side draft may help hold the plow in position.

For a sulky plow, the horizontal line of draft is about 2" to 3" to the furrow side of the shin, and parallel to the open furrow. On most sulky plows, if three horses are hitched abreast and an outside horse walks in the open furrow, side draft is sure to result. This side draft occurs because the center of power of a three-abreast is farther away from the furrow wall than the plow’s true line of draft, causing the horses on the land to pull at an angle to the open furrow. As a result, the front of the plow is forced toward the furrow, and the bottom has a tendency to run out.

This side draft, if not excessive, may be largely offset by angling the furrow wheel toward the furrow wall just enough to keep the plow from shifting out. The side draft also forces the landside of the plow against the furrow wall. If the furrow wheel must be angled to the point that it crushes, or tries to climb up the furrow wall, adjust the hitch to lessen the angle and try to reduce the side draft.

On high-lift (framed) plows, when the center of pull is hitched to the plow’s true line of draft, the rear furrow wheel should be either straight or angled slightly to lead away from the furrow wall. If the hitch cannot be made on the true line of draft, the resulting side draft may be counteracted to some degree by setting the front furrow wheel to angle toward the furrow wall, and the rear wheel to angle farther away from the furrow wall.

A tandem hitch eliminates the possibility of side draft and allows three or four horses to be used. Plow equalizers are available designed to eliminate side draft when using a 4-abreast team.

A sulky plow equipped with a tongue should be set as close as possible to the center of the space between the horses. Most plows have an adjustment that allows the tongue to be moved sideways.

Usually a 40" doubletree with a twohorse team on a 14" sulky plow results in the team’s center of power and the plow’s line of draft being nearly in line and causes little side draft. When using three horses, with a 55" evener and a 33" doubletree, hitch the evener to the plow clevis approximately 8" to land of the plow’s center of draft to keep the right horse (when using a right-hand plow, or the left horse on a left-hand plow) in the furrow.

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The horizontal line of draft for this sulky plow is about 2" to 3" to the furrow side of the shin and parallel to the open furrow. Moving the hitch point to accommodate a three-abreast team causes side draft, which may be offset by angling the furrow wheel toward the furrow wall; if the furrow wheel must be angled to the point that it crushes, or tries to climb, the furrow wall, reduce the side draft by adjusting the hitch.
Common Plow Troubles

If you’re having a problem plowing, before making any adjustments be sure you’re familiar with the procedures described in the accompanying paragraphs and drawings. If you make any adjustment that doesn’t correct the problem, return that adjustment to its former position before trying something else.

Probably the most common (and most frustrating) cause of poor plowing is the failure of the moldboard to scour. Temporarily setting the coulter wide or plowing deeper may help get the moldboard polished. Running the plow fast in light, sandy soil should do the job as well. Once the moldboard has attained a bright land polish, preserve it by liberally coating the polished parts with grease after each use.

If the moldboard is rusty, remove rust with a wire brush or sandpaper. If it has been painted or varnished—primarily a problem with a new or freshly painted plow—clean off the coating with paint remover.

Non scouring may be affected by speed. Plow bottoms are designed to run at a certain speed. If the operation is too slow, especially in sticky soil, non scouring will result. Poor scouring may also result from excessive side draft, causing the plow to run crooked. Finally, check adjustments and make sure the plow is level. Once you have a bright, shiny moldboard, if you are still having trouble, the following solutions may help.

 Plow won’t take a full cut—
 * Make sure the furrow wheel assembly is set correctly.
 * Move the hitch clevis toward the furrow.
 * Check the angle of the furrow wheel.

 Furrow wheel tries to climb the furrow wall—
* Make sure the furrow wheel assembly is set correctly.
* Move the hitch clevis toward the land.
* Check the angle of the furrow wheel.

Plow won’t penetrate or stay in the ground—
* Check the share for wear.
* Move the hitch point up.
* In hard ground, check the coulter adjustment.
* Make sure the traces are not too short.

Plow runs too deep or hops along on the point—
* Move the hitch point down.
* Check your depth setting.
* Make sure the traces are not too long.

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Author
Sam Moore was a contributor to Rural heritage Magazine for many years. This article appeared in the Evener 2008 issue of Rural Heritage magazine.

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