GEAR APPLICATION GUIDE · PLASTIC GEAR · PL02

Nylon Gears for Agricultural Machinery:
PA6, PA66 and MC Nylon Agricultural Drive Applications

Agricultural machinery nylon gears occupy a unique position in the materials selection landscape — they must withstand outdoor temperature extremes from −30°C winter storage to +70°C summer field operation, sustained exposure to soil dust, agrochemicals (herbicides, fungicides, insecticide sprays), fertiliser pellets, diesel fuel, and hydraulic oil, and the shock and impact loading that characterises all agricultural implement drives where unpredictable field conditions (rocks, roots, clods, wet headland soil) transmit sudden overloads to the gear train. Nylon gears in agricultural equipment address a different need than steel gears: not to carry higher loads, but to provide overload protection through controlled tooth deformation and failure that absorbs shock energy and protects the steel shaft and housing from damage, or to operate without lubrication (dry running) in sealed agricultural implement gear cases where access for oiling is impractical, or to reduce inertia and noise in high-cycle-rate metering mechanisms where the gear operates millions of cycles per season.

PA6 · PA66 · MC Nylon · GF30 · MoS₂ · M2–M8
−30°C to +70°C · Agrochemical Resistant · Dry Run
Seeder · Spreader · Harvester · Sprayer · PTO

MATERIAL GRADES

PA6 / PA66 / MC

Agricultural nylon gear material grades. PA6 (Nylon 6): most common, good balance of toughness, low cost. PA66 (Nylon 66): 20% higher strength and heat resistance than PA6, preferred for higher-temperature agricultural drive applications. MC Nylon (cast PA6): higher crystallinity and lower moisture absorption than injection-moulded PA6, preferred for large gears above M5 where cast process is more economical than injection moulding

MODULE RANGE

M2 – M8

Agricultural nylon gear module range. Seeder seed metering: M2–M3 (high precision, low load, millions of cycles/season). Fertiliser spreader metering disc drive: M3–M4. Rotary mower intermediate gear: M4–M6. PTO-driven auxiliary implement: M5–M8. Grain elevator cup belt drive: M3–M5. Overload protection gear (sacrificial): M4–M6 — sized to fail before the steel shaft at overload

TEMP RANGE

−30°C / +70°C

Agricultural nylon gear operating temperature range. PA6 and PA66 embrittle below −20°C (Charpy notch impact energy drops steeply); for cold-climate agricultural use (Canada, Scandinavia, Russia), impact-modified nylon grades (PA6 + 5% rubber impact modifier) maintain useful toughness to −40°C. Upper limit: continuous 70°C for standard PA6/PA66; 100°C for PA66 GF30; 120°C for MC nylon in low-load applications

KEY ADDITIVE

GF30 / MoS₂

GF30 (30% glass fibre reinforced) increases nylon gear flexural strength by 2.5× and thermal deflection temperature from 65°C to 210°C (PA66 GF30) — the most important additive for high-load agricultural nylon gears. MoS₂ (2% molybdenum disulphide) reduces the friction coefficient from 0.35–0.45 (dry PA6) to 0.15–0.20, making MoS₂-filled nylon gears suitable for dry-running agricultural drives where re-lubrication is impossible

Nylon Gear Advantages in Agricultural Machinery — Shock, Dry Running, and Weight

The selection of nylon gears over steel gears in agricultural machinery is driven by three distinct engineering rationales that each apply to different machine subsystems. The first rationale is shock absorption and overload protection — a nylon gear at M5 in a rotary mower drive has approximately 15–20% of the tooth stiffness of the equivalent steel gear. When the mower blade hits a buried rock, the impact load is absorbed by the elastic deformation of the nylon gear teeth and, in a worst-case event where the nylon gear teeth shear, the controlled failure of the nylon gear prevents the steel gearbox housing, shaft, and bearing assembly from being damaged. The nylon gear is designed as the weak link in the drive chain — a sacrificial element that absorbs the impact energy and can be replaced in the field in minutes, rather than sending the gearbox back to a repair workshop. The cost of a replacement nylon gear is typically 5–15% of the cost of a replacement steel gearbox, making the nylon gear overload protection philosophy economically very attractive for agricultural equipment where field stone impacts are unavoidable.

The second rationale is dry-running capability in sealed gear cases where lubrication access is impractical. Korea Ever-Power’s nylon gears for agricultural machinery include MoS₂-filled PA6 and PA66 grades for dry-running applications — seeder seed metering gears, fertiliser spreader rate gears, and grain cart drive gears where the sealed gear case is filled once at manufacture and cannot be re-lubricated in the field. The MoS₂ particles in the nylon matrix act as a solid lubricant, coating the mating steel or nylon gear tooth surface with a continuous MoS₂ film that reduces the boundary friction coefficient from 0.35–0.45 (dry PA6 against steel) to 0.15–0.20, extending the gear wear life by 3–5× compared to unfilled PA6 in the same dry-running agricultural application. The third rationale is reduced inertia in high-cycle metering mechanisms — a seeder seed metering wheel that cycles 200 times per minute over a 10-hour working day accumulates 120,000 cycles per day and perhaps 3 million cycles per season. The reduced inertia of a nylon gear (density 1.14 g/cm³ vs 7.85 g/cm³ for steel — nearly 7× lower) means the metering drive servo motor or ground-wheel drive must supply significantly less torque for the acceleration phase of each metering cycle, reducing the drive energy consumption and wear on the metering mechanism over the season.

The moisture absorption behaviour of nylon is the most important limitation that must be understood before specifying PA6 or PA66 gears for outdoor agricultural use — nylon absorbs atmospheric moisture and this moisture absorption causes dimensional swelling and a reduction in the gear’s modulus of elasticity and yield strength. A PA6 gear tooth that is machined or moulded to its specification tooth thickness at 50% relative humidity (the standard conditioning condition for nylon gear design) will have a tooth thickness approximately 0.3–0.5% larger at 100% RH (fully conditioned, outdoor storage in rain) due to moisture absorption expansion. This swelling increases the tooth thickness and reduces the backlash at the gear mesh — in a steel housing with tight backlash design, the swollen nylon gear can jam against its mating gear after outdoor storage in wet conditions, producing a jammed drive mechanism when the operator first uses the equipment at the start of the season. Korea Ever-Power agricultural nylon gears are dimensioned with a moisture absorption allowance — the tooth thickness is machined to the driest expected condition (typically 40% RH at the design temperature) with sufficient backlash to accommodate the full-wet expansion at 100% RH without jamming. The moisture swelling allowance is calculated and stated in the gear design documentation for each agricultural application.

nylon spur gear agricultural machinery PA6 PA66 Korea Ever-Power
Korea Ever-Power PA66 GF30 (30% glass fibre reinforced nylon 66) agricultural machinery gear — M5, 24T, OD 130 mm, face width 40 mm, bore 30 mm H7, machined from extruded GF30 rod stock. PA66 GF30 material: flexural strength 210 MPa (vs 80 MPa unfilled PA66), tensile strength 175 MPa, HDT 210°C at 1.8 MPa load — the GF30 reinforcement makes this material suitable for higher load agricultural drives where standard unfilled PA66 would creep under sustained tooth contact pressure at 40–50°C ambient operating temperature in summer field conditions. The gear tooth profile is machined (not moulded) — for M5 agricultural gears in GF30, machining from rod stock is preferred over injection moulding because: (a) machining allows the tooth root fillet radius to be optimised for maximum fatigue resistance rather than being constrained by mould tool geometry, and (b) machined GF30 gears do not have the surface skin of resin-rich material that injection moulding produces, which can delaminate from the glass-reinforced core under impact loads. Korea Ever-Power agricultural PA66 GF30 gears are used as OEM components in seeders, fertiliser spreaders, and rotary tedder drives for major agricultural equipment manufacturers in Europe, North America, and Australia.

Agricultural Nylon Gear Application Specifications

APPLICATION 01

PRECISION SEEDER
SEED METERING

Nylon gear specification: PA6 or PA66 injection moulded (M2–M3, tight dimensional tolerance ±0.05 mm on tooth thickness for seeding rate accuracy), MoS₂-filled for dry running, high cycle endurance ≥ 3 million cycles per season, agrochemical resistance (herbicide seed treatment contact). Precision seeder seed metering wheels use small nylon gears to drive the seed disc or finger pickup metering elements — the gear ratio between the ground wheel and the metering element determines the seeds per metre seeding rate, and the accuracy of that ratio (no lost motion from backlash or tooth wear) determines the seeding population accuracy that modern row crop seeding requires (±2% plant population at 80,000 plants/ha). Korea Ever-Power seeder metering nylon gears are injection moulded in PA6 with 2% MoS₂ for dry running, in sets covering the standard gear ratio changes used by the major seeder brands (John Deere, Kinze, Monosem, Horsch, KVERNELAND) to adjust the seeding rate across different row widths and crops. The gear sets include both the main metering drive gear and the intermediate idler gear, since replacing only the main gear without replacing the worn idler restores only part of the lost motion — the idler must be replaced as a set for the seeding rate accuracy to be fully restored.

APPLICATION 02

FERTILISER SPREADER
RATE CONTROL

Nylon gear specification: PA66 GF30 injection moulded or MC nylon machined (M3–M5), chemical resistance to ammonium nitrate, urea, MAP/DAP fertiliser dust and moisture, M5 gears with reinforced boss for high-torque disc drive, bright UV stabiliser additive for outdoor storage. Fertiliser spreader rate change gears (the interchangeable gear sets that the operator installs to set the application rate for different fertiliser products and target rates) are a high-volume aftermarket spare part for disc spreaders, pendulum spreaders, and granular fertiliser distributors. The nylon gear must resist the corrosive combination of hygroscopic fertiliser dust (which absorbs moisture and produces a dilute acid/salt solution on the gear surface) and UV degradation from outdoor storage between seasons. Korea Ever-Power fertiliser spreader nylon gears use PA66 GF30 with a UV stabiliser package (0.5% Tinuvin 770 HALS light stabiliser) to prevent UV degradation of the nylon matrix during outdoor storage. The GF30 reinforcement provides the chemical resistance to fertiliser contact — the glass fibres are chemically inert to all standard fertiliser chemicals — and the higher flexural strength accommodates the torque from the disc drive at maximum application rates (which can create disc drive torques of 80–150 Nm in heavy spreading conditions) without creep at the tooth contact.

APPLICATION 03

ROTARY MOWER /
TEDDER DRIVE

Nylon gear specification: MC nylon machined (M5–M8), overload protection design (tooth yield at 3–4× rated torque to protect the steel gearbox housing from rock impact damage), agrochemical resistant surface, OD ≥ 100 mm (most economical as machined MC nylon from cast billet rather than injection moulded). Rotary mower and tedder intermediate drive gears are the primary application for overload protection nylon gears in agricultural equipment — the nylon gear is intentionally designed to shear its teeth at a controlled torque level (3–4× the rated drive torque) that is above the normal operating range (including the resistance peaks from heavy windrow or matted grass) but below the torque that would damage the steel gearbox housing, housing bolts, or intermediate shaft. This design philosophy (using the nylon gear as a sacrificial torque limiter) is more reliable than a slip clutch or shear bolt in a drive train that experiences continuous torque variation from the grass cutting process — a shear bolt must be replaced after each overload event, a slip clutch may slip at the wrong moment during normal high-load cutting, but a nylon gear with controlled yield strength provides a consistent, repeatable overload protection level that remains in service through thousands of high-load cutting cycles before the accumulated tooth deformation reduces the drive torque below the required level, indicating the need for replacement.

plastic nylon gear agricultural machinery Korea Ever-Power range
Korea Ever-Power nylon and plastic gear range for agricultural machinery applications — from M2 injection-moulded PA6 seeder metering gears (foreground, low load, high cycle) to M8 MC nylon machined rotary mower drive gears (background, overload protection, controlled yield). The material selection follows a clear logic based on the gear’s function in the agricultural machine: M2–M3 seeder and spreader metering gears are injection moulded PA6 or PA66 with MoS₂ for dry running and precision dimensional control; M4–M6 intermediate drive and rate control gears are PA66 GF30 injection moulded for the combination of strength and chemical resistance; M6–M8 overload protection and mower drive gears are MC nylon machined from cast billet for the most economical production of large-diameter agricultural gears. Korea Ever-Power produces all three categories in-house and maintains the complete range for major agricultural equipment brands as both OEM supply (minimum 500 pieces per order) and aftermarket supply (minimum 10 pieces per order for replacement parts). Complete material test reports (tensile strength, flexural modulus, impact strength, moisture absorption, and chemical resistance) are available for all agricultural nylon gear materials on request.
OEM tractor agricultural gear nylon steel Korea Ever-Power
Korea Ever-Power OEM agricultural gear components showing the material and function diversity of the agricultural machinery gear application — steel tractor PTO and transmission gears (foreground, 20CrMnTi carburized for high-torque power transmission) alongside nylon implement drive gears (not shown, supplied separately as metering and overload protection components for the same agricultural machine builder). Many modern agricultural machines combine steel gears in the primary power transmission path with nylon gears in the implement metering and control functions — Korea Ever-Power is one of very few gear suppliers who can manufacture both steel and nylon agricultural gears to OEM specification under a single quality system and provide a consolidated supply for the agricultural equipment manufacturer. This consolidated supply simplifies the machine builder’s supplier qualification (single audit, single quality agreement) and improves the dimensional compatibility between the steel and nylon mating gears — Korea Ever-Power controls the steel gear OD and nylon gear bore dimensions from the same set of drawings, ensuring the steel-to-nylon mesh centre distance and backlash are consistent across all production batches.

Frequently Asked Questions — Nylon Gears for Agricultural Machinery

Q 01

Our seeder nylon rate change gears are wearing out after only 2 seasons of use — the tooth tips show heavy abrasive wear marks and the seeding rate has become inaccurate. We use the seeder for canola and cereals in heavy soils. What is the cause and should we upgrade the material?

Accelerated abrasive wear on seeder nylon rate change gears in heavy soils (clay loam or heavy clay) is a well-recognised problem — the soil dust that enters the unsealed seed metering mechanism contains quartz particles of 50–200 μm that are harder than the nylon gear surface (Mohs hardness of quartz: 7; Mohs hardness of nylon: approximately 2). When this abrasive dust reaches the gear mesh, it acts as a lapping compound, wearing the tooth flanks at a rate that is 5–10× higher than the gear-to-gear wear in a clean environment. The wear appears concentrated at the tooth tip because the highest relative sliding velocity (and therefore the highest abrasive action) occurs at the addendum contact zone. Root causes and solutions: (1) Improve the metering mechanism sealing: if the seed metering unit can be fitted with a dust cover or labyrinth seal around the gear case, reducing the soil dust entry is the most effective first step. Even a simple foam seal around the gear case perimeter can reduce abrasive ingress by 60–70% and extend the nylon gear life proportionally. (2) Upgrade to PA66 GF30 from unfilled PA6: the glass fibre reinforcement in PA66 GF30 increases the tooth surface hardness (by creating a glass-fibre-reinforced surface layer) and significantly improves the abrasive wear resistance — GF30 nylon gear tooth wear rate in abrasive environments is typically 30–50% lower than equivalent unfilled PA6 gears. Korea Ever-Power seeder metering gears are available in PA66 GF30 as a direct dimensional replacement for PA6 gears — the same tooth count, module, and bore dimensions. (3) Consider a MoS₂ + GF15 combined compound: for the most severe abrasive conditions (stony, sandy soils), a PA66 with GF15 (15% glass fibre, lower than GF30 to preserve toughness) plus 2% MoS₂ provides both the solid lubrication to reduce gear-to-gear wear and the glass reinforcement to resist abrasive particle wear. Korea Ever-Power can supply this combined compound grade at M2–M4 for seeder metering gears on request — lead time 15–20 days for injection moulded quantities above 200 pieces.

Q 02

We are designing a new precision fertiliser spreader for the Australian market. Can Korea Ever-Power supply the complete nylon rate change gear set for OEM supply, and what is the minimum order quantity for injection moulding?

Korea Ever-Power provides a complete OEM nylon gear supply service for new agricultural equipment designs — from initial material specification and gear geometry design through injection mould tooling, production, and ongoing supply. For a new precision fertiliser spreader OEM supply programme: New OEM design process: (1) Customer provides the required gear ratios (application rates), input speed, output torque, and environmental conditions (agrochemical exposure, temperature range, outdoor UV exposure duration). (2) Korea Ever-Power recommends the nylon grade (PA66 GF30 with UV stabiliser for outdoor Australian conditions, where UV degradation is more aggressive than in European climates due to higher UV index) and calculates the gear geometry for each rate change ratio. (3) Injection mould tooling is designed and manufactured at Korea Ever-Power — multi-cavity tooling for high-volume gear sets (typically 4–8 cavities for M2–M4 gears) to achieve the per-piece cost required for OEM supply pricing. (4) First article samples from production tooling submitted to the customer for dimensional verification and field trial approval. (5) Series production commences on customer approval. Minimum order for injection moulding: For new tooling (customer-owned mould): minimum 500 pieces per gear design for the first order (to justify the tooling investment amortisation), then 200 pieces per subsequent order. For existing Korea Ever-Power standard agricultural gear sizes (standard tooth count and module combinations in the Korea Ever-Power catalogue): minimum 50 pieces per order from existing tools, with lead time 10–15 days. Australian market specific requirements: Korea Ever-Power can supply agricultural nylon gears with the UV stabiliser package appropriate for Australian UV conditions (Tinuvin 770 or Tinuvin 622 HALS stabiliser at 0.5–1.0% loading), confirmed by accelerated weathering test (1,000 hours Xenon arc per ISO 4892-2) before OEM supply approval.

Q 03

What is the correct procedure for storing agricultural nylon gears at the end of the season, and are there any precautions needed if the gears have been exposed to herbicide or seed treatment chemicals?

Agricultural nylon gear end-of-season storage is important for preserving the dimensional accuracy (particularly the tooth thickness, which determines the seeding rate or application rate accuracy) and the material integrity for the next season. Recommended procedure: (1) Clean before storage: remove nylon gears from the metering mechanism and clean with water (not petroleum solvents — most organic solvents attack the nylon surface, causing surface crazing that accelerates wear) and a soft brush to remove soil, seed treatment chemical residue, and fertiliser deposits. Seed treatment chemicals (fungicide + insecticide + film polymer coating slurry) can deposit a film on the gear tooth surface that hardens during storage and changes the tooth geometry by filling the root fillet radius — clean this off while the deposit is still soft (within 24 hours of use). (2) Dry thoroughly before storage: nylon gears stored in a damp condition (on a workbench in a wet machinery shed) absorb moisture continuously, causing the tooth thickness to swell beyond the design value. When reinstalled at the start of the next season, the swollen gear may jam in the metering mechanism. Store nylon gears in a dry location — inside a sealed plastic bag with a silica gel desiccant sachet is the best approach for gears that will be stored for more than 3 months. (3) Herbicide-exposed gears — specific precaution: glyphosate-based herbicides (Roundup and equivalents) are chemically compatible with PA6 and PA66 nylon at normal contact concentrations. However, some formulated herbicide products contain surfactants (POEA — polyethoxylated tallow amine) that can swell certain nylon grades at high concentration or prolonged contact. If gears from herbicide-treated seed (seed treatments with glyphosate tolerance coatings) show surface swelling or softening, test the gear in clean water for 24 hours — if the swelling resolves, the gear is still serviceable; if the surface remains soft or shows surface crazing, replace with Korea Ever-Power PA66 GF30 (glass reinforcement significantly improves chemical resistance vs unfilled PA6). (4) UV stabiliser requirement for outdoor summer storage: if gears will be stored outdoors (on the implement in the field) between spring and the autumn seeding season, specify Korea Ever-Power gears with UV stabiliser package to prevent surface chalking and embrittlement from direct summer UV exposure.

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Need Nylon Gears for Agricultural Machinery?

Korea Ever-Power manufactures PA6, PA66, PA66 GF30, and MC nylon gears for all agricultural machinery applications — seeder metering (M2–M3, MoS₂ dry running, ±0.05 mm accuracy), fertiliser spreader rate gears (PA66 GF30, UV stabilised, agrochemical resistant), and rotary mower overload protection gears (MC nylon machined, controlled yield design). OEM tooling service for new machine designs, aftermarket replacement from 10 pieces. ISO 9001:2015 certified.

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