Light Disc Harrow Guide: Sizes for 12–55 HP and How to Adjust It

A light disc harrow is the most useful seedbed tool for small and medium farms: it breaks clods after ploughing, chops weeds and residue, and levels the field in one pass behind a 12–55 hp tractor. The problem is that many buyers get a good machine but a poor finish, because the size, gang angle and levelling are not set for their tractor and soil. This guide covers all three.

What a Light Disc Harrow Does

A light disc harrow has two or four gangs of concave discs on a three-point frame. The gangs are set at an angle to the direction of travel, so each disc cuts, lifts and turns a thin slice of soil. Front and rear gangs face opposite ways, which throws soil out and then back in and leaves the surface level.

It is a secondary tillage tool. After a disc plough or mouldboard plough has turned the land, the harrow breaks the clods into a fine tilth. On light, sandy or already loose soil it can also be the only tillage pass before sowing.

SH Light Disc Harrow Models and Specifications

Our 1SH-L light series is three-point mounted, with 460 mm discs and a working depth of 100–140 mm. All figures are taken from our disc harrows page.

Model	Working width (mm)	Working depth (mm)	No. of discs	Disc diameter (mm)	Weight (kg)	Matching power (hp)
1SH-L1.1	1100	100–140	12	460	200	12–18
1SH-L1.3	1300	100–140	14	460	220	15–18
1SH-L1.5	1500	100–140	16	460	250	20–25
1SH-L1.7	1700	100–140	18	460	270	25–30
1SH-L2.0	2000	100–140	20	460	380	35–40
1SH-L2.2	2200	100–140	22	460	400	40–45
1SH-L2.3	2300	100–140	24	460	420	55

Specifications are for reference; customisation is available.

Which Disc Harrow for Small Tractor Farms?

Pick the model by tractor power first, then check width against your wheel track.

• 12–18 hp compact tractors: 1SH-L1.1 or 1SH-L1.3.
• 20–30 hp: 1SH-L1.5 or 1SH-L1.7, the most common choice for family farms.
• 35–55 hp: 1SH-L2.0 to 1SH-L2.3 for more output per hour.

The working width should cover the tractor wheel marks so tyre tracks are worked out. In heavy clay or very dry ground, stay at the lower end of each power range. If you need more weight to cut into hard soil, look at the medium series. Our disc harrow size chart compares light and medium models side by side, and the selection assistant lists every model for your horsepower.

How to Adjust a Disc Harrow: Step by Step

Most complaints about a new harrow come from setup, not from the machine. Follow these steps the first day in the field.

1. Hitch and centre. Attach the harrow to the three-point linkage and adjust the lower link check chains so it sits in the centre behind the tractor without swinging.
2. Level side to side. Adjust the lift rod on the tractor until both ends of the frame are the same height above the ground.
3. Level front to rear. Use the top link. If the front gang digs deeper than the rear, the field will be ridged; shorten or lengthen the top link until both gangs work at the same depth.
4. Set the disc harrow angle. Start with a small gang angle. A larger angle makes the discs cut deeper, break more clods and mix more residue, but it also needs more power.
5. Test and adjust. Drive 30–50 metres, stop and check clod size and depth, then change one setting at a time.

Speed matters too. A steady, moderate speed gives the best finish. Too slow and clods are not broken; too fast and the harrow bounces and leaves an uneven surface. Two passes at a smaller angle, the second across the first, often give a better seedbed than one aggressive pass.

Notched or plain discs? Notched discs bite into hard ground and chop residue; plain discs give a smoother finish. A common set-up is notched discs on the front gang and plain discs on the rear.

Light or Medium Disc Harrow?

A light harrow is the right tool for seedbed work in loam and sandy soil, vegetables, rice paddies after draining and small fields where turning space is tight. Step up to the medium 1SH-M series (Category II, 560 mm discs, 25–80 hp) when you work heavy clay, thick corn stalks or sun-baked ground, or when your tractor is over 55 hp. For primary tillage of hard land, a heavy offset harrow or a plough comes first.

Maintenance and Spare Parts

• Grease the gang bearings according to the service schedule and check them for play before each season.
• Tighten gang bolts after the first hours of work; loose gangs wear discs and spools quickly.
• Replace discs when the diameter has worn down noticeably, because small discs lose depth.
• Clean off soil and residue, oil the disc surfaces and store the harrow under cover.

We supply plain and notched replacement discs and bearing assemblies, so dealers can stock parts with each machine. See our harrow discs range.

Common Buying Mistakes

• Buying a width the tractor cannot pull at full depth.
• Leaving the frame out of level, then blaming the discs for ridges.
• Using maximum gang angle on the first pass in dry soil.
• Not ordering spare discs and bearings with the first shipment.

Why Buy Direct from the Factory

Shenghang builds light, medium, heavy and folding disc harrows in our own factory and sells factory direct, with SH labelling, OEM options, export packing and shipping by sea, rail or air – see export and shipping. Dealers can mix harrows, seeders and spare discs in one container. Good seedbed preparation is part of sustainable agricultural mechanization, because fewer, better passes save fuel and time.

Light Disc Harrow FAQ

What size disc harrow for a 25 hp tractor?

The 1SH-L1.5 is listed for 20–25 hp and the 1SH-L1.7 for 25–30 hp. In heavy soil choose the 1SH-L1.5.

How do I adjust a disc harrow angle?

Loosen the gang clamps, move the gangs to the next angle position and retighten. Start small and increase until clods break to the size you want.

Can a 3 point disc harrow replace a plough (plow)?

On light, loose soil it can be the only tillage pass. On hard or weedy land, plough first and use the harrow to finish the seedbed.

Why does my disc harrow leave ridges?

Usually the frame is not level front to rear, so one gang works deeper. Adjust the top link until both gangs cut at the same depth.

Get a Quote

Send us the model (for example 1SH-L1.7), quantity, your tractor HP and destination port on WhatsApp +86 133 8469 2372, and we will reply with a quotation and packing details. Compare all series on our light disc harrow and disc harrow page.