It's easy to set the ST740 mulch-till ripper


There are just four easy steps to setting the ST740. You will need a 6-foot tape measure.

1. Set shank depth.
Use the shank-depth decal on the machine to select the proper depth-stop for the depth desired. Always install equal size stops on both lift cylinders. (Check number of notches.)

2. Level the frame.
With the unit raised on a flat surface in the field, measure the distance from the top of the main “frame to the ground” at both the front and the rear. Adjust the hitch-turnbuckle as needed, so the front and rear “frame to the ground” measurements are the same. (When the unit is lowered into the soil the main frame must operate parallel with the soil surface.)

3. Set the front gang depth.
Lower the unit so the points are on the ground. Measure the distances from the bottom of the “blades to the ground”. This measurement should equal “shank depth less 2-1/2 inches” for a good starting point. The left setting and right setting must be equal.

4. Set the rear gang depth.
With the unit still on the ground measure the rear gang depths. Set it to equal shank depth less two inches for a good starting point. The left setting and right setting must be equal.

The ST740 is designed to operate between five to seven mph. The front gang-blades should be set only deep enough to cut the residue. Adjust the front gangs deeper if the residue is not getting completely cut.

Fine-tune the rear gang depth to leave a level surface at operating speed. Front and rear gang depth settings are usually not the same.

Important: If the front gangs are set too deep, the rear gangs will not be able to fill the center valley.

For proper spacing between passes run the second outside front blade in the mark left by the rear gang’s outside tri-lobe blade. This will leave the proper 30-inch spacing between shanks. Driving too wide will leave a low area between passes.

Final rechecks
Be sure the ST740 frame is operating level. Measure the front left and right gang cylinder stops (or turnbuckles “pin to pin”) to be sure both sides are set at equal depths.

Check the rear settings also. (An unequal setting “side to side” will cause the unit to pull crooked.)

Performance features

1. The ST740 uses the industry’s shallowest concavity disk blades on an 18-gang angle for the front cutting-gangs.

  • At equal depths shallow blades pull easier because soil and residue are not moved as far laterally.
  • Shallow concavity blades are less speed sensitive giving a wider speed-operating window without throwing soil past the rear blades.
  • Shallow concavity blades have less backpressure and penetrate hard soil easier and deeper, more like a coulter.

2. The ST740 uses deep concavity blades on 16-gang angle for the rear leveling-gangs.

  • Deep concavity blades move, roll, and mix more residue and soil at shallower depths.
  • The deep concavity blades roll the loosened soil to break clods and fill behind the shanks, leaving a leveler, more uniform surface profile.

3. ST740 adjusts the front and rear gang depths separately.

  • Different functions require separate settings to achieve uniform output.
  • The front cutting-gang’s function is to cut residue and open hard soil.
  • The rear leveling-gang’s function is to level loosened soil ridges while mixing the residue into the surface soil.

4. ST740 doesn’t need gang angle adjustment.

  • Lessening blade angle changes the flow, and creates more pressure on the backside of the blades, which tends to decrease the depth of cut, and the ability to cut the residue.
  • Increasing blade angle changes the flow, which would make the unit more speed sensitive and increases the power requirement.
  • The ST740 can achieve the desired flow of residue and soil by simply changing the gang depth.


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