Setting a disc? Do it right in five easy steps

Feb 24, 2017 | Tough Tillage Update

Aerial view of F15 Double Offset Tandem Disc Harrow

Whether you’re managing residue, working a seedbed, or prepping for the next crop rotation, a properly set disc is crucial. By taking a little extra time to check your disc, you can ensure you make fewer trips to the field, reduce the risk of erosion, and lay the level groundwork for a successful crop.

To help you reap the benefits of a properly set disc, AMCO has put together this guide to setting our disc harrows.


Before making any adjustments, make sure the tractor is in park and the key is removed. Use extreme caution when performing the following steps. Never put yourself between pinching points.

To make sure the disc is correctly attached to the tractor, check that you have:

  • Installed the drawbar, pin, and lock pin
  • Removed and stored the jack
  • Installed the safety chain
  • Connected all hydraulic hoses and lighting connectors
  • Checked all tire pressures
  • Lubricated all grease points

Once you’ve finished prepping the disc, put it in a travel position and move it to level ground where you can continue with the next steps.


If you are using a folding disc like AMCO’s F15 Double Offset Tandem Disc Harrow, the next step is to level the wings so the blades cut at an even depth across the unit. This step is especially important if you are using a disc with differently sized tires on the wings and the center section, which can cause uneven cutting.

Start by raising and lowering the disc and folding it for four cycles to purge any air in the lines and make sure the phasing cylinders are in sync. Next, with the disc still in transport position, use the rockshaft height adjustment to level the wings. The gap between the blade and the ground should measure the same across the disc.

Did you know?

The gangs of AMCO’s F15, F17, and LTF Double Offset Tandem Disc Harrows overlap, ensuring you get 100% tillage all the way across the disc.

Diagram of F15 Double Offset Tandem Disc Harrow


Whether you’re using a 3-point disc (LTF, LOF, Wicked Warrior) or a pull-type harrow (F15, F17, D41, F41-42, J41-44, G2), it is important to correctly set the front and rear gangs for a smooth finish. As a general rule, set the front blades to cut approximately ¾” deeper than the rear. Shallow cuts will cause buildup in the middle (sometimes known as “watermelon rows”). Cutting too deeply on the front will cause the outer edge to leave a berm. Results will vary at different speeds.


Closeup of depth gauge control arm

AMCO’s standard mechanical depth controls ensure an even cutting depth.

Tillage depth will depend on your crop, soil conditions, and speed. As a general rule, the depth is 25% of the blade diameter in normal operating conditions.

AMCO discs come standard with mechanical depth controls. To begin, raise the wheels and engage the blades in the ground at the desired cutting depth. Set the depth controls to guarantee each cut is the same depth.

If the disc is equipped with front gauge wheels, set them to the same height as the rear tires. This will keep the disc from cutting too deeply on the edges in uneven areas.

Make a short pass (approximately 30 yards) at normal operating speed and then stop. Leave the blades in the ground, dig behind the center blades of the front and rear gang, and measure the depth of the blade furrow. Make adjustments and repeat until the front and rear gangs are cutting at desired depths.


If the disc is properly adjusted, you should see an even mixture of soil and residue, a level seedbed floor, and a level soil surface. If there are ridges, carefully repeat the above steps. A smooth finish indicates that the disc is ready for use.

Taking the time to properly adjust your disc will set you up for a successful planting season. For more specific instructions on how to set your disc model, review the operating manual or contact an AMCO tough tillage expert.

Visit our website’s Disc Harrow, 3-Point Disc/Lift Harrow, and Wheel Offset Harrow pages to learn more about AMCO’s industry-leading disc harrow lineup.

Need to narrow it down? Choose a product category.