Plastic Sprockets | Nylatron, Acetal, Nylon — FDA-Approved, Self-Lubricating, Corrosion-Free

Plastic Sprockets 1

Korea Ever-Power #25 plastic sprockets — Nylatron, Acetal, Nylon, and UHMW — are the correct choice when steel sprockets corrode, contaminate, spark, or make too much noise. Self-lubricating polymer material eliminates grease in food-grade and clean-room applications. FDA-approved grades are available for direct food contact. Plastic tooth deflection under load means several teeth simultaneously share the working load — giving roller chain load capacity that matches the full working load of the #25 chain despite the non-metallic material.

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When Plastic Sprockets Outperform Steel — Six Scenarios Where Material Matters

Steel sprockets are the default for most roller chain drives, and rightly so — they are strong, machinable, and inexpensive. But steel fails in a specific set of environments that are common in Korean food production, pharmaceutical manufacturing, chemical processing, and electronics facilities. In each of these scenarios, plastic is not a compromise — it is the engineering-correct material selection:

 Plastic Sprockets 1

①
Wet and wash-down environments. Steel sprockets corrode in daily wash-down cycles even when zinc-plated or black-oxide coated. Rust particles contaminate products on conveyor surfaces below. Plastic sprockets are inherently corrosion-free — no coating to degrade, no rust to shed, indefinite service life in wet conditions as long as load limits are observed.
②
Lubrication-free zones. In food processing, pharmaceutical production, and clean-room electronics assembly, chain lubricant is a contamination risk. Plastic sprockets are self-lubricating — the polymer material contains internally distributed lubricant that migrates to wearing surfaces during operation, eliminating the need to apply external grease or oil to the sprocket-chain interface.
③
Noise-sensitive environments. Plastic sprocket teeth deflect slightly under load, damping the impact pulse as each chain roller engages a tooth. This elastic buffering reduces the metallic impact noise of steel-on-steel engagement by a measurable margin. In food packaging lines, office automation equipment, and medical device conveyors where noise levels are regulated or customer-visible, plastic sprockets provide quieter operation without speed reduction.
④
Chemical resistance. Specific polymer grades resist acids, alkalis, oxidising agents, and solvents that attack steel or stainless steel at different concentrations. In electroplating, pharmaceutical, and chemical processing facilities where chain drives operate in the presence of process chemicals, choosing the correct polymer grade provides corrosion immunity that no metallic sprocket can match.
⑤
Non-magnetic and non-conductive requirements. MRI facilities, electronic assembly lines, and certain precision instrument environments require non-magnetic and/or non-conductive drive components. Engineering polymers are inherently non-magnetic and electrically non-conductive — properties that no steel alloy can provide regardless of treatment.
⑥
Chain wear reduction. Plastic sprocket teeth are softer than steel chain rollers. Counter-intuitively, this is beneficial: the softer tooth acts as the sacrificial wear element rather than the chain roller. In low-load applications the plastic tooth wears slowly while extending roller life — the sprocket is cheaper to replace than the chain. The tooth deflection behaviour simultaneously reduces impact stress on roller pins and bushings.

Stock #25 Plastic Sprocket Specifications — Nylatron B-Hub Series

Standard stock #25 plastic sprockets are manufactured in Nylatron (nylon with molybdenum disulfide — see material section below) in B-hub style. Pitch diameter is the functional engagement diameter corresponding to #25 chain pitch (6.35 mm). Length through bore is the hub engagement depth for keyway and set screw retention. Stock bore sizes listed are minimum standard bores — larger bores to the maximum physically possible are machined to customer specification.

Sprocket Size Teeth Material Pitch Dia. (in) Stock Bore Length Thru Bore
25B10 10 Nylatron 0.81″ 1/4″ 0.485″
25B11 11 Nylatron 0.89″ 1/4″ 0.485″
25B12 12 Nylatron 0.97″ 5/16″ 0.485″
25B13 13 Nylatron 1.05″ 5/16″ 0.485″
25B14 14 Nylatron 1.13″ 5/16″ 0.485″
25B15 15 Nylatron 1.20″ 5/16″ 0.485″
25B16 16 Nylatron 1.28″ 5/16″ 0.485″
25B17 17 Nylatron 1.36″ 5/16″ 0.485″
25B18 18 Nylatron 1.44″ 3/8″ 0.485″
25B19 19 Nylatron 1.52″ 3/8″ 0.485″
25B20 20 Nylatron 1.60″ 3/8″ 0.485″
25B21 21 Nylatron 1.68″ 3/8″ 0.485″
25B22 22 Nylatron 1.76″ 3/8″ 0.485″
25B24 24 Nylatron 1.91″ 3/8″ 0.485″
25B26 26 Nylatron 2.07″ 3/8″ 0.485″
25B28 28 Nylatron 2.23″ 3/8″ 0.485″
25B30 30 Nylatron 2.39″ 3/8″ 0.485″
25B36 36 Nylatron 2.87″ 1/2″ 0.610″
25B40 40 Nylatron 3.19″ 1/2″ 0.610″
25B48 48 Nylatron 3.82″ 1/2″ 0.610″
25B54 54 Nylatron 4.30″ 1/2″ 0.610″
25B60 60 Nylatron 4.78″ 1/2″ 0.443″

Plastic Sprocket Materials — Nylatron, Acetal, Nylon, and UHMW Compared

The polymer grade is not a cosmetic choice — it determines load capacity, temperature range, chemical resistance, and whether the sprocket meets FDA or USDA requirements for food contact. Korea Ever-Power supplies #25 plastic sprockets in four standard materials and can source additional engineering polymer grades for specialised applications:

Property Nylatron (MoS₂ Nylon) Acetal (POM) Nylon (PA6/PA66) UHMW-PE
Self-lubrication Excellent (MoS₂ filler) Good Good Very Good
Abrasion resistance Very Good Good Good Outstanding
Tensile strength ~80–85 MPa ~60–70 MPa ~60–85 MPa ~25–40 MPa
Max continuous temp 100–115°C 90–110°C 100–120°C 80–100°C
Moisture absorption Low (MoS₂ reduces) Very Low (~0.2%) Moderate (2–8%) Near zero
Dimensional stability (wet) Good Excellent Poor (swells in water) Excellent
FDA / Food contact Grades available FDA-approved grades FDA grades available FDA-approved
Ideal application Dry, load-bearing, precision drives Wet environments, close-tolerance parts General dry conveyor duty Abrasive environments, food contact

Note on Nylon in wet environments: Plain nylon (PA6 or PA66) absorbs moisture, which causes dimensional swelling that can tighten the bore on the shaft and alter the pitch diameter. In wash-down or immersion applications, specify Acetal (POM) or UHMW-PE instead — both have negligible moisture absorption and maintain dimensional stability across wet operating cycles.

Three Hub Configurations for #25 Plastic Sprockets

Plastic sprockets are available in the same A-plate, B-hub, and C-hub configurations as steel sprockets. The hub geometry affects shaft engagement length and torque capacity — critical even in plastic, where the plastic material limits the maximum transmissible torque per unit of shaft engagement area.

Types of Plastic Sprockets

Minimum axial thickness. Suitable for flush-mount, weld-on, and light torque positions. Bore passes through flat plate body only — limited keyway depth available.
Hub projects from one face, providing longer bore engagement for keyway and set screw. Standard configuration for most drive positions. Stocked in Nylatron 10–60T.
Hub on both faces for maximum shaft engagement. Specified for higher-torque positions within plastic sprocket limits. Non-stock — custom lead time 2–3 weeks.

Matching #25 Plastic Roller Chain — Acetal, Delrin, and Nylatron

For a fully contamination-free, lubrication-free, non-metallic chain drive system, the sprocket and chain should be specified in compatible polymer materials. Korea Ever-Power supplies matching #25 plastic roller chain in three standard materials to pair with the sprockets above:

Types of chain

 

#25 Acetal (POM) Chain
Lowest moisture absorption. Best dimensional stability in wet environments. FDA-approved. Ideal for food wash-down lines.

 

#25 Delrin Chain
DuPont Delrin acetal — close-tolerance precision. High stiffness for positioning drives. Low friction, chemical resistant.

 

#25 Nylatron Chain
MoS₂-filled nylon. Best self-lubrication of the three. Matched to Nylatron sprockets for compatible wear pairing.

When pairing plastic chain with plastic sprockets, material compatibility between chain and sprocket affects the wear interface. Matching Nylatron chain to Nylatron sprockets keeps the wear pair within the same material family; using Acetal chain with Nylatron sprockets is also common because the different polymers produce a low-adhesion wear couple. Avoid pairing two identical soft polymers in high-load drives — the similar hardness can produce higher adhesive wear than a dissimilar polymer pair. For a fully validated plastic chain and sprocket system for your specific application, contact us with your polymer preference, chain speed, load, and environment.

Custom-Engineered Plastic Sprockets — Non-Standard Requirements

Plastic chain 2

Standard Nylatron B-hub sprockets cover the majority of #25 plastic sprocket applications. For non-standard requirements, Korea Ever-Power provides custom-machined plastic sprockets:

  • Non-standard polymer grades — PTFE (Teflon) for chemical resistance beyond Acetal/Nylon; Polypropylene for specific acid environments; Kynar (PVDF) for fluoride and halogen environments; oil-filled nylon for sustained high-cycle duty
  • Metric chain sizes — custom plastic sprockets for 06B, 08B, 10B, and other DIN 8187 metric chain sizes in any of the above polymer grades
  • Double pitch plastic sprockets — C2040 and C2050 compatible profiles in Acetal or UHMW for food conveyor applications where metal is excluded entirely
  • A-plate and C-hub styles — non-stock configurations in any tooth count from 10 to 72 teeth, machined to drawing from solid polymer bar or plate
  • Idler plastic sprockets — plain bore or bronze bushed bore for free-running idler positions in fully non-metallic conveyor systems

Custom plastic sprockets typically have a lead time of 2–3 weeks from receipt of confirmed drawing or specification. Provide ANSI chain size, tooth count, hub style, bore diameter, key dimensions, and polymer grade. We will return a drawing for approval before machining.

Where #25 Plastic Sprockets Are Specified in Korean Industry

🍱 Food Processing and Packaging

Korean instant food, snack packaging, and beverage filling lines use #25 Acetal or UHMW plastic sprockets on transport chain drives within the food contact zone. No lubrication required eliminates the HACCP risk of chain oil contaminating packaged product. Acetal's near-zero moisture absorption maintains precise chain pitch under daily steam cleaning and wet operating conditions typical in Korean food plants.

🔬 Clean Room and Electronics

Semiconductor wafer handling systems, PCB component transport, and LCD panel conveyors in Korea's electronics manufacturing sector require non-magnetic and non-particle-shedding drive components. Nylatron plastic sprockets satisfy both requirements — no magnetic attraction to semiconductor components, and the MoS₂ lubricant is retained within the polymer matrix rather than shedding as particles into the clean air environment.

💊 Pharmaceutical Manufacturing

GMP-regulated pharmaceutical tablet and capsule lines in Korea require documented material compliance for all components in contact with or above the product stream. FDA-approved Acetal and UHMW grades provide the USP Class VI biocompatibility documentation needed for GMP dossiers. No external lubricant means no lubricant carryover into product packaging.

Why Korea Ever-Power Chain and Sprocket

Korea Ever-Power plastic sprocket precision CNC machining Nylatron Acetal

Korea Ever-Power Chain and Sprocket Co., Ltd. supplies the complete #25 plastic sprocket range with material documentation and custom engineering capability:

✦Full 10–60T Nylatron B-hub range in stock — no MOQ; single units available for prototype and replacement orders
✦Multiple polymer grades available — Nylatron, Acetal, Nylon, UHMW-PE, and specialist grades (PTFE, Kynar, Polypropylene) for custom orders
✦FDA-approved material grades documented — material certificates confirming FDA 21 CFR compliance available for food, pharma, and GMP procurement requirements
✦Custom bore machining — finished bore with stainless set screws; custom polymer grades and non-standard tooth counts available from CNC-machined solid bar
✦Matched plastic chain in stock — #25 Acetal, Delrin, and Nylatron chain supplied alongside sprockets for fully non-metallic drive systems
✦Material selection consultation — describe your wash-down chemicals, operating temperature, and compliance requirements and we confirm the correct polymer grade before your order

Frequently Asked Questions

How much load can a plastic #25 sprocket transmit compared to a steel one?
Plastic sprocket teeth deflect elastically under load, which allows multiple teeth to simultaneously share the working load — unlike steel where load is concentrated on one or two teeth at any moment. The result is that a correctly-specified plastic sprocket can match the full working load of the #25 chain at low to moderate speeds. The limiting factor is temperature and speed: above approximately 1.5 m/s or 60°C, the polymer's creep resistance decreases and load capacity drops. For #25 plastic sprockets, the maximum recommended transmitted power is approximately 0.2–0.5 kW depending on speed — confirm with the material data sheet for your chosen polymer grade.
Why does Nylon swell in water but Acetal does not?
Nylon (polyamide) contains amide groups in its polymer backbone that form hydrogen bonds with water molecules — the polymer literally absorbs water into its structure, causing swelling. Equilibrium moisture content in humid air is 2–4% for PA6, up to 8% for PA6/66 in immersion. This swelling translates to bore tightening and pitch diameter change. Acetal (polyoxymethylene, POM) does not have amide groups — its ether linkages do not bond with water. Moisture absorption is below 0.2% even in prolonged immersion. For sprockets in wash-down or immersed applications, Acetal is always the correct choice over plain Nylon.
Can plastic sprockets run with standard steel #25 chain, or do I need plastic chain?
Plastic sprockets run with standard ANSI #25 steel chain without any modification. The tooth profile is identical to the steel sprocket version and the #25 chain dimensions are unchanged. In fact, steel chain with plastic sprockets is a common combination — the softer tooth face reduces chain roller wear by acting as the sacrificial element rather than the chain. Use all-plastic chain only when the application specifically excludes metal (food contact zone, MRI, wash-down with metal detection). All-plastic chain has a much lower tensile strength than steel and should not be used as a direct substitute for steel chain without checking the load rating.
What does "FDA-approved" mean for plastic sprockets — which regulation applies?
FDA compliance for plastic materials in food equipment is governed by 21 CFR (Code of Federal Regulations). Acetal used in food-contact applications typically complies with 21 CFR 177.2470; UHMW-PE complies with 21 CFR 177.1520. These regulations specify which additives and processing aids are permitted in materials that will contact food. "FDA-approved" in this context means the polymer formulation (including any colorants or stabilisers) is manufactured from ingredients on the FDA's approved substance lists. When ordering for food-contact applications, specify that you require a material certificate confirming FDA 21 CFR compliance and we will include it with the delivery documentation.
What is the maximum operating temperature for plastic sprockets?
Practical maximum continuous service temperatures: Nylatron 100–115°C, Acetal 90–110°C, plain Nylon 100–120°C, UHMW-PE 80–90°C. These are the temperatures at which the material maintains adequate creep resistance under load — if the temperature exceeds the limit, the polymer creeps and the sprocket teeth gradually deform under repeated tooth loading. Momentary excursions above these temperatures during start-up or steam cleaning are tolerable if brief. For applications above 100°C, specify glass-fibre-reinforced nylon (GF Nylon) or consider metallic sprockets — contact us with your temperature profile for a material recommendation.
How do I install a plastic sprocket on a shaft with a keyway?
Plastic sprockets with finished bores include a machined keyway and two stainless steel set screws. Installation is the same as a steel sprocket: align the keyway, slide onto the shaft with the key fitted, and tighten the set screws to the specified torque (typically 3–6 Nm for M4–M6 stainless set screws in Nylatron or Acetal). Do not over-torque — the set screw can compress and crack the hub material if torqued beyond the plastic's compressive yield point. For plastic hub sprockets, finger-tight plus one quarter turn is the correct tightening approach; use thread-locking compound rather than high torque to prevent the set screw from backing out during operation.

Customer Reviews

Verified feedback from customers in Korea and surrounding markets.

Park Soo-bin, Food Safety Engineer, Instant Noodle Manufacturer, Gyeonggi-do (early 2025)

"We converted our seasoning powder dosing line from steel to Acetal plastic sprockets specifically because HACCP required us to eliminate all lubricant within 600mm of the open product stream. The Acetal 25B20 sprockets from Korea Ever-Power have been running 14 months now without lubrication and without measurable pitch diameter wear. Material compliance certificates were provided on delivery as we require for GMP documentation."

Kim Dong-young, Equipment Engineer, Semiconductor Fab, Gyeonggi-do (Q4 2024)

"Our wafer carrier transport system needed non-magnetic, non-conductive drive components due to ESD sensitivity of the product. Korea Ever-Power supplied Nylatron 25B18 sprockets with finished bores. The MoS₂ content in Nylatron specifically concerns some ESD-sensitive process managers — we tested and confirmed no particle contamination in our clean-room air quality monitoring after six months of operation. Suits the application."

Jeong Hae-jin, Maintenance Engineer, Pharmaceutical Tablet Line, Chungbuk (2025)

"We specify Acetal plastic sprockets for all chain drives in our GMP tablet compression area. FDA 21 CFR certificates are a regulatory requirement for our product dossier. Korea Ever-Power has consistently provided the required documentation with delivery. Lead time for standard sizes is 10 days. We now order annually in batches to maintain a 6-month on-site replacement stock."

Oh Sung-hyun, Design Engineer, Office Automation Equipment OEM, Seoul (early 2025)

"We use #25 Nylatron sprockets in paper feed drives because the noise reduction versus steel is immediately perceptible — and important for office equipment. The tooth deflection characteristic also absorbs paper jam impact loads without tooth cracking, which was a problem with small steel sprockets on the same mechanism. Korea Ever-Power supplies in the exact bore and keyway we specify, with 9-day lead time."

Han Min-seong, Process Engineer, Chemical Plant, Ulsan (2024)

"We needed #25 plastic sprockets for a conveyor inside a chlorine gas handling enclosure — steel corrodes immediately in that atmosphere and stainless steel has a stress corrosion cracking risk with chloride. Korea Ever-Power recommended PVDF (Kynar) for this specific application, custom-machined to our tooth count and bore requirements. Six months in and zero corrosion — the material recommendation was technically sound."

 

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