Agricultural pillow block bearings are not one commodity. A disk harrow gang, a square-shaft planter, and a clean grain conveyor place different demands on bore geometry, sealing, lubrication, and housing. The practical choice is usually not between brands first, but between a disk harrow bearing, a square bore unit, a round bore unit, or a standard pillow block insert that fits the implement interface.

This guide maps those choices for farmers, farm equipment OEMs, and distributors. It uses LDK product data and manufacturing facts to show how to match mounted units to soil, harrow, and implement applications, and where stainless steel or plastic options matter when washdown or corrosion is present.

Problem Definition: The Bore and the Environment Decide the Bearing

Most agricultural bearing failures begin with a mismatch. A round bore bearing forced onto a square shaft, a sealed-for-life unit used where grease renewal is required, or a painted cast iron housing used in frequent washdown can shorten service life even when the bearing itself is correctly manufactured. The first decision is therefore the shaft interface and the operating environment, not the catalogue page.

In tillage, the bearing sees soil, dust, shock, and moisture. In planting and seeding, the shaft may be square, and the bearing must follow that geometry. In grain handling and fans, a standard two-bolt pillow block may be the simplest fit. In washdown or fertilizer exposure, stainless steel or plastic housings become relevant. Each case points to a different mounted unit.

Industry Background: Agricultural Mounted Bearings Are a Configured Family

LDK is the brand of Deyuan Smart Technology (Fujian) Co., Ltd, a bearing manufacturer established in 1986 in Fujian, China. The company operates a 90,000 m2 facility with approximately 130 employees, a 12-engineer R&D team, and an annual output of 15,000,000 units. LDK states an annual sales figure of US$15 million and exports about 60% of output to Europe, North America, Latin America, and Oceania.

Its portfolio includes cast iron pillow blocks, thermoplastic housed bearing units, all stainless-steel mounted ball bearing units, Accu-Grip concentric locking bearing units, mounted units for the air handling industry, rod ends, spherical plain bearings, and farm implement bearings. Insert bearing bore sizes range from 10 mm to 140 mm, with more than 100 combinations of materials and housing types. LDK also states in-house production of both bearings and housings in one place.

Quality and testing support the agricultural range. LDK holds IATF 16949 and ISO 9001 quality certifications, and its testing capabilities include fatigue life, tensile strength, noise and vibration, and salt spray testing. For buyers, those capabilities matter because agricultural bearings are often judged by contamination resistance, fit, and consistency across repeat orders.

Detailed Solution: Match the Mounted Unit to the Implement Interface

The agricultural range separates into four practical groups: disk harrow bearings, square bore farm implement bearings, round bore farm implement bearings, and standard pillow block inserts with cast iron housings. Stainless steel and plastic units sit alongside these groups for washdown and corrosion exposure.

Disk harrow bearings for soil-engaging gangs

Disk harrow bearings are listed as disk harrow bearing units. Models include ST491A, ST491A-I, ST491A-II, ST491B, ST491B-I, ST491B-II, DHU45R-209, DHU55R-211, DHU55R-211-I, DHU40S-211, FD211-1 1/2, ST209-1 1/8, ST209-1 1/8-1, ST209-1 1/8-11, ST211-1 3/4, ST211-2 3/16, and ST211-2 3/16-1. These units use a round bore or square bore, a triple-lip seal, and are mounted in two stampings. They are relubricable and made from chrome steel GCr15/AISI52100.

For a disk harrow gang, confirm the gang shaft geometry and the stamping pair before ordering. The two-stamping mounting is part of the unit definition, not an accessory choice. The relubricable design also means the maintenance plan should include grease access at the gang position. If the gang runs in abrasive soil or frequent moisture, the seal and grease interval deserve more attention than the housing paint.

Square bore agricultural bearings for square shafts

Square bore farm implement bearings include W208PPB13, W208PPB6, W208PP5, W208PPB5, W208PP8, W208PPB8, W208PPB11, W208PPB12, W209PPB5, W210PP4, W210PPB4, W211PP3, W211PPB3, W211PP5, and W211PPB6. They are square bore, triple-lip sealed, pre-lubricated and non-relubricable, and made from chrome steel GCr15/AISI52100.

Square bore units are selected when the implement shaft is square and the bearing must follow that shaft geometry. Because the listed square bore units are pre-lubricated and non-relubricable, they suit positions where the bearing is intended to run as a sealed unit. For high-hour or high-contamination positions, compare the intended life and replacement interval with a relubricable disk harrow or standard pillow block arrangement.

Round bore agricultural bearings for round shafts

Round bore farm implement bearings include 205PPB7, W208PPB7, W208PP10, W208PPB23, W209PPB2, W209PPB4, W210PP2, W210PPB2, W211PP2, and W211PPB2. They are round bore, triple-lip sealed, pre-lubricated and non-relubricable, and made from chrome steel GCr15/AISI52100.

Round bore units fit round shafts and simpler alignment conditions. They are often the direct replacement choice when the original implement used a round shaft and a sealed farm implement bearing. If the shaft is worn or the mounting is misaligned, correcting the shaft and mounting before bearing selection is more important than changing the bearing family.

Standard pillow block inserts and cast iron housings

Standard pillow block bearing inserts include UC2 standard duty with a 12 mm to 90 mm shaft range, UC3 heavy duty with a 25 mm to 140 mm range, UCX medium duty with a 25 mm to 75 mm range, and UK2 with a tapered bore and adapter sleeve locking from 20 mm to 80 mm. These inserts use a wider inner ring and set screw locking, except UK2, which uses a tapered bore and adapter sleeve. They are self-aligning and relubricable.

Matching cast iron housings include UCP2 standard duty from 12 mm to 100 mm, UCPX medium duty from 25 mm to 100 mm, and UCP3 heavy duty from 25 mm to 140 mm. The housing material is HT200 cast grey iron with dark green paint, and the insert is chrome steel. These two-bolt pillow blocks are listed for agriculture machinery among other industries, including fans, conveyors, and material handling. When the mounting is a frame rather than a base, UCF four-bolt flange units use the same insert families.

Locking method is a separate decision. UCP2 uses set screw locking. UEP2 uses concentric locking, NAP2 uses eccentric locking, and UKP2 uses adapter sleeve locking. If vibration tends to loosen set screws, review the locking method rather than only increasing torque.

Stainless steel and plastic options for washdown and corrosion

Where washdown, fertilizer, chemical, or humid exposure matters, LDK lists stainless steel and plastic mounted units. Stainless steel inserts include SUC2 with a 440 stainless steel insert from 12 mm to 60 mm, plus SUE2, SUER2, SSB2, SSA2, SNA2, SUK2, and SSER. Stainless steel units include SSUCP2..ESB with a 304 stainless steel housing and 440 stainless steel insert from 20 mm to 60 mm, set screw locking, food grade grease and silicon rubber seal, and an operating temperature range of -35°C to 102°C. SSUCF2..ESB provides a four-bolt flange option.

Plastic bearing units include TP-SUCP from 12 mm to 60 mm with a PBT thermoplastic housing, 440 stainless steel insert, set screw locking, food grade grease and silicon rubber seal, and -35°C to 102°C operation. TP-SUCF, TP-SUCFL, TP-SUCT, TP-SUET, and TP-SUCPA provide other housing shapes. Waterproof plastic bearing units such as WP-SSBP use a PA6 thermoplastic housing and 440 stainless steel insert from 20 mm to 40 mm. The thermoplastic housing also has a TÜV Rheinland food-contact test report to U.S. FDA CFR Title 21, certificate 168263398a 001.

These units are not automatic upgrades for every agricultural position. They are selected when the corrosion or washdown risk is high enough to justify the material change. For dry soil-engaging positions, the cast iron and chrome steel agricultural ranges remain the direct fit.

Step-by-Step Breakdown: From Shaft Measurement to Production Order

1. Measure the shaft and identify the bore geometry. Record the shaft diameter and whether the interface is round or square. Check for wear, burrs, and previous bearing marks. The bore geometry is the first filter because a square bore unit and a round bore unit are not interchangeable on the same shaft.
2. Choose the bearing family by implement function. For a disk harrow gang, start with the disk harrow bearing range. For a square-shaft implement, start with the square bore range. For a round-shaft implement, start with the round bore range. For a standard two-bolt pillow block position, start with UCP2, UCPX, or UCP3 and the matching UC2, UCX, or UC3 insert.
3. Confirm the mounting and housing. Disk harrow units are mounted in two stampings. Standard pillow blocks use a two-bolt base. Flange mountings use UCF or SSUCF styles. Confirm hole spacing, base height, and whether the housing must be cast iron, stainless steel, or thermoplastic.
4. Select the seal and lubrication. Agricultural round bore, square bore, and disk harrow bearings use a triple-lip seal. Disk harrow bearings are relubricable; the listed round bore and square bore farm implement bearings are pre-lubricated and non-relubricable. Standard UCP units are relubricable. Match the lubrication plan to the maintenance access at the implement.
5. Match the material to the environment. Use HT200 cast grey iron and chrome steel for general agricultural positions. Use 304 stainless steel housings with 440 stainless steel inserts for washdown and corrosive exposure. Use PBT or PA6 thermoplastic housings with 440 stainless steel inserts where plastic units are preferred and the temperature range is suitable.
6. Validate a sample before production. Check shaft fit, mounting hole alignment, locking method, grease condition, and the certificate or test report for the ordered series. For OEM projects, LDK offers technical remote support and customization capabilities that include prototyping and durability, safety, and performance testing.
7. Plan the production order. For OEM programs, LDK states a MOQ of 5,000 units, monthly capacity of 300,000 units, and lead time of 30 to 90 days. Confirm the final MOQ and schedule by model, material, housing, and order mix.

Use Cases: Where Each Agricultural Bearing Fits

Disk harrow and tillage gangs. Use the disk harrow bearing range when the bearing is mounted in two stampings on a gang. The triple-lip seal and relubricable design match the soil and shock exposure of tillage. Confirm the gang shaft is round or square before selecting the model.

Planters and seeders with square shafts. Use the square bore range when the implement shaft is square. The listed W208PPB and W210PPB/W211PPB models are pre-lubricated and non-relubricable, so they suit sealed-unit positions with planned replacement.

Round-shaft implements. Use the round bore range for round shafts and simpler alignment. The 205PPB7 and W208/W209/W210/W211 round bore models cover common farm implement positions.

Fans, conveyors, and clean material handling. Use UCP2, UCPX, or UCP3 cast iron pillow blocks with UC2, UCX, or UC3 inserts. These are two-bolt, self-aligning, relubricable units listed for agriculture machinery and other industrial equipment.

Washdown, fertilizer, and chemical exposure. Use SSUCP2..ESB stainless steel units or TP-SUCP plastic units when corrosion risk is high. For a waterproof plastic pillow block in the 20 mm to 40 mm range, WP-SSBP is the listed option. Confirm temperature, load, and mounting before substituting a cast iron unit.

OEM replacement and private label programs. LDK offers OEM and ODM production, private labelling, custom packaging, FMEA, 8D problem solving, traceability, and technical remote support. These capabilities matter when an agricultural OEM needs a repeatable bearing specification across multiple production lots.

Comparison Table: Agricultural and Standard Mounted Units

FAQ

What quality and compliance documents can support an agricultural bearing order?

LDK holds IATF 16949 and ISO 9001 quality certifications. Quality control includes self-inspection and verification, second-party audit, and third-party audit. SGS RoHS verification reports are available for specific scopes such as UFL002, UCFC205, UC206 L3, SB205, PF205, and UCF207 L3. For an agricultural order, request the report and certificate that match the exact series and market. The thermoplastic housing also has a TÜV Rheinland food-contact test report to U.S. FDA CFR Title 21, certificate 168263398a 001, where that housing is used.

Can LDK supply disk harrow, square bore, and round bore units from one source?

Yes. LDK's portfolio includes farm implement bearings, and the listed agricultural ranges cover disk harrow bearings, square bore bearings, and round bore bearings. LDK also produces cast iron pillow blocks, stainless steel units, and plastic units. The company states insert bearing bore sizes from 10 mm to 140 mm and more than 100 combinations of materials and housing types, with in-house production of bearings and housings.

What MOQ and production capacity apply to OEM agricultural bearing programs?

For OEM programs, LDK's stated capability includes a MOQ of 5,000 units, monthly capacity of 300,000 units, and lead time of 30 to 90 days. Actual MOQ and schedule depend on the model, material, housing, and order mix, so confirm them in the RFQ.

How should a buyer validate a sample before a full order?

Request a sample of the exact bore, seal, lubrication, and housing material. Check shaft fit, mounting hole spacing, locking method, grease condition, and the certificate or test report for the ordered series. For OEM projects, LDK offers technical remote support and customization capabilities that include prototyping and durability, safety, and performance testing. Confirm the sample approval criteria before production.

What lead time should an OEM plan for?

Plan 30 to 90 days for OEM production as stated in LDK's OEM capability. Add time for sample approval, packaging approval, and any custom grease, label, or housing requirement. LDK states at least 95% on-time delivery performance for its OEM capability. To start, send the shaft drawing and annual demand to LDK for a sample and quote review.

Conclusion

For agricultural equipment, the reliable decision sequence is shaft geometry, implement function, mounting, seal and lubrication, then housing material. Disk harrow bearings fit two-stamping gang positions and are relubricable. Square bore farm implement bearings fit square shafts and are pre-lubricated and non-relubricable. Round bore farm implement bearings fit round shafts with the same sealed-unit logic. Standard UCP2, UCPX, and UCP3 pillow blocks cover two-bolt positions with relubricable inserts. Stainless steel and plastic units are reserved for washdown or corrosion exposure.

LDK's combination of in-house bearing and housing production, IATF 16949 and ISO 9001 quality systems, agricultural bearing ranges from 10 mm to 140 mm bore, and OEM support gives farmers and OEMs a practical starting point for specification review. The final step is always sample validation against the actual shaft, mounting, and maintenance plan.

Deyuan Smart Technology (Fujian) Co., Ltd (LDK), Xi Pu Industry Park, He Shi, Luo Jiang, Quan zhou city, Fujian Province, P.R.China. Zip: 362013.