Agricultural Machinery & Farm Equipment: Disc Plow Working Principle, Adjustment

Farmers worldwide prefer tractor disc plows for their superior adaptability across harsh field conditions:

Penetrates hard, dry compacted soil where standard mouldboard plows fail to break ground

Anti-clog performance on sticky clay soil, eliminating soil sticking issues common with mouldboard plow shares

Delivers reliable deep tillage performance for root layer loosening

Operates safely on stony, root-filled fields with low risk of component breakage

Maintains stable tillage even with partially worn discs, great for abrasive sandy soil

Resists blockage when working loose, light-textured farmland

Fitted with scrapers to achieve full soil inversion and bury crop residues & weeds

Without scrapers, it delivers stronger soil mixing instead of complete furrow turning

Low maintenance cost: no frequent sharpening or replacement of plow shares required

Not suitable for high-speed tillage; optimal cutting performance requires low tractor travel speed
Less thorough residue and weed burial effect compared to mouldboard ploughs
Leaves rougher tilled ground with more large soil clods after operation
Heavier unit under identical working width; disc plows rely on dead weight for penetration instead of mouldboard plow suction effect

Popular tractor-compatible models include 3-bottom mounted standard disc plow, 6-bottom trailed standard disc plow, 4-bottom mounted reversible standard disc plow.

Structural Features

Multiple inclined disc blades fixed on a heavy-duty frame supported by transport wheels. Most standard units come with 3–6 steel discs, each offering 18–30cm single cutting width.

Disc tilt angle: 15–25° backward from vertical plane

Disc cutting angle (disc angle): 42–45° against tractor forward travel direction

Standard disc diameter: 61–71cm

Disc material: 5–10mm thick heat-treated high-carbon steel for wear resistance

Scraper Function

Mounted scrapers assist full residue coverage and prevent sticky clay buildup on disc surfaces during continuous tillage.

Reversible Disc Plow (Mounted / Semi-Mounted)

Fitted with dedicated hydraulic reversing mechanism to flip disc angles at field headlands, enabling one-way consistent tillage without manual plow readjustment when turning around field ends.

Application & Weight Specs

Standard disc plows rely on self-weight for soil penetration (no suction effect like mouldboard plows), perfectly matched for hard, arid farmland. Total unit weight ranges 200–600kg.

Mounted disc plow: Tractor front tires bear lateral side thrust; optional support wheel relieves partial side load

Trailed disc plow: Dedicated furrow wheel undertakes all lateral traction force

Two core adjustable angles determine tillage depth, width and soil inversion quality for tractor disc plows:

Disc Angle: The included angle between disc cutting plane and tractor travel direction, factory standard 42–45°

Tilt Angle: The offset angle between disc cutting plane and vertical line, factory standard 15–25°

Tilt Angle Adjustment Methods

Reposition plow posts on the main frame

Shift adjustment blocks to alter vertical offset

Swap mounting grooves on bearing brackets to change fixed tilt angle

Under identical soil conditions and tillage volume, tractor disc plows generate lower draft pull than mouldboard plows. For extremely hard compacted ground, extra counterweights on transport wheels boost disc penetration but increase overall tractor draft demand. Bearing friction and scraper contact also slightly affect total traction load.

1. Improve Soil Penetration Ability

Increase disc angle for deeper ground penetration

Reduce tilt angle to strengthen disc digging force

Add front/rear counterweights on the plow frame Working depth range: 7.6cm (3 inches) to 38.1cm (15 inches). Regular disc edge sharpening guarantees consistent penetration performance.

2. Adjust Single Disc Cutting Width

Modify the angular position between land wheel axle and main frame to change working width

Widen cutting width by increasing disc angle and decreasing tilt angle

Fault Symptom	Root Cause	Repair & Adjustment Solution
Insufficient tillage depth	1. Dull disc cutting edges2. Insufficient plow dead weight3. Overlarge tilt angle	1. Grind and sharpen disc edges2. Install additional counterweights3. Readjust tilt angle to standard range
Excessive tractor draft pull	1. Blunt disc blades2. Overwide furrow cutting width	1. Sharpen worn discs2. Reduce tilt angle to narrow furrow width
Overheavy lateral side traction	Incorrect three-point hitch connection with tractor	Reconnect plow following standard mounting specifications
Poor scraper soil cleaning performance	Misaligned or damaged scrapers	Readjust scraper mounting position or replace broken scrapers
Uneven furrow surface after tillage	1. Inconsistent disc angles across all blades2. Loose disc bearings3. Malfunctioned tractor hitch assembly	1. Unify disc angle for all discs2. Tighten or replace worn bearings3. Inspect, repair and calibrate tractor hitch parts