Stock Bore Sprockets & Platewheels Asian Standard

pignoni e ruote standard-1

Korea Ever-Power Asian standard stock bore sprockets (NK series) are the unfinished-bore version of the Asian standard range — the hub is supplied with the bore at a pilot size, ready for the customer to machine to any required shaft diameter, keyway and tolerance. This is the preferred specification for non-standard shaft sizes, shaft diameters that fall between the fixed bore sizes in the finished bore (FBN/FBK) range, and for OEM applications requiring tight bore tolerances or non-standard keyways.

Categoria:
Richiedi informazioni ora

25B – 120B

Chain Size Range

NK Series

Type NK & Platewheels

Any Bore

Machined to Specification

JIS B1801

Asian Standard

Asian Standard Stock Bore Sprockets & Platewheels – Product Overview

The NK designation stands for the type hub used throughout the Asian standard sprocket series — a plain cylindrical hub with a pilot bore, supplied with minimum wall thickness at the hub to allow boring to any diameter up to the maximum bore listed for that tooth count. The tooth profile conforms to JIS B1801, the same standard as the finished bore range. Material is C45 carbon steel with induction-hardened tooth flanks for 35B and above.

In addition to standard toothed sprockets, this series also includes platewheels (DP type) — solid disc rings with JIS chain tooth profile, used where a flat plate is needed instead of a spoked or hubbed sprocket for attachment chain or specialised conveyor drives. Platewheels are produced in the same chain sizes and tooth counts as NK sprockets.

Korea Ever-Power Asian standard NK stock bore sprockets JIS B1801 platewheels

📐 NK Hub Dimension Key

Symbol Meaning
Do Tip (outside) diameter (mm)
Dp Pitch circle diameter (mm)
BD min Pilot bore diameter (mm)
BD max Maximum finished bore (mm)
BL Hub bore length (mm)
* prefix Max bore with recessed hub groove for chain clearance

NK Stock Bore vs FBN Finished Bore — Which to Order?

The choice between NK stock bore and FBN finished bore is primarily determined by shaft diameter and whether the bore falls within the pre-machined bore options in the finished bore range.

Situation NK Stock Bore FBN Finished Bore
Shaft is a standard JIS bore size (e.g. 20, 22, 25 mm) ✔ Can be used ✔ Faster — arrives ready
Shaft is between standard sizes (e.g. 28 mm, 33 mm) ✔ Machine to exact size ✖ Not available in that bore
Non-standard tolerance required (H5, H6, interference fit) ✔ Machine to any tolerance ✖ H7 only as standard
Large Z count not in FBN range ✔ Full Z range available ✖ Limited to catalogue bores
Platewheel (solid disc) required ✔ DP platewheel variant ✖ Not available
No machining facility on site ✖ Requires lathe ✔ Ready to fit

NK Stock Bore Sprocket Specifications — 35B through 60B

NK35B  |  Pitch 9.525 mm  |  Roller Ø 5.08 mm  |  Inner width 4.78 mm

Z Do (mm) Dp (mm) BD min (mm) BD max (mm) BL (mm)
9 32 27.85 9.5 *21.5 20
12 41 36.81 9.5 *30.5 20
17 57 51.84 11.5 41 20
25 81 76.00 11.5 57 20
36 114 109.08 11.5 62 20
57 176 172.91 11.5 67 20

NK40B  |  Pitch 12.70 mm  |  Roller Ø 7.92 mm  |  Inner width 7.85 mm

Z Do (mm) Dp (mm) BD min (mm) BD max (mm) BL (mm)
9 42 37.13 8.5 *28 22
12 55 49.07 11.5 *40 22
15 67 61.09 13.5 *46 22
17 76 69.12 13.5 54 22
25 108 101.33 13.5 70 22
38 158 153.80 13.5 80 22

NK60B  |  Pitch 19.05 mm  |  Roller Ø 11.91 mm  |  Inner width 12.70 mm

Z Do (mm) Dp (mm) BD min (mm) BD max (mm) BL (mm)
9 63 55.70 11.5 *43 32
13 89 79.06 14 57 32
17 113 103.67 16 73 32
21 139 127.82 16 83 40
25 165 152.00 16 90 40
38 237 230.78 16 100 40

* = max bore with hub groove for chain clearance. NK25B, NK50B, NK80B, NK100B and NK120B also available — contact us. Platewheels (DP type) available in all chain sizes. Specify chain size, tooth count and required bore diameter mm when ordering. Keyway to JIS B1301.

Caratteristiche tecniche

Recessed Hub Groove (* Max Bore)

Where the maximum bore is preceded by an asterisk (*), the bore at that size requires a recessed groove machined into the hub bore at the chain face to provide clearance for the inner link plates of the chain. This groove prevents the inner plates from contacting the hub bore and creating a friction drag on the chain. Always confirm the bore diameter does not exceed the maximum — exceeding it removes the minimum hub wall required for the groove and for the setscrew thread.

Platewheels — DP Type

Platewheels (DP type) are solid ring sprockets without a traditional hub — the bore is centrally positioned in a solid disc of the same outer diameter as the equivalent NK sprocket. Used for attachment chain, K-series chain and any application where the chain plates are wider than a standard tooth profile allows. Platewheels are also used as idler sprockets where the chain must be guided past a shaft on a solid disc rather than engaging individual teeth through standard tooth profile.

Full Tooth Count Flexibility

The NK stock bore range covers tooth counts from Z=9 to Z=114 for most chain sizes — far beyond the finished bore range which is limited by the available bore sizes in each hub diameter. For speed ratios requiring large sprocket diameters, or for replacement of worn large-tooth-count sprockets, the NK stock bore series provides the complete range. Specify the exact tooth count and bore diameter — non-catalogue tooth counts can also be produced on order.

JIS B1801 Tooth Profile

The NK stock bore sprocket tooth profile is the same JIS B1801 form as the finished bore range. Pair with Asian standard JIS B1801 roller chain of the matching chain size designation. Remember: 40B chain requires NK40B sprocket, not #40 ANSI sprocket or 08B European sprocket — the roller diameters differ between standards even at the same pitch.

Korean OEM Industrial Equipment

All Korean industrial machinery uses JIS-based chain standards internally. NK stock bore sprockets are the standard OEM specification for non-standard shaft sizes in Korean conveyor, textile, construction and processing equipment. The ability to machine to any bore makes NK the universal specification for Korean OEM engineering departments that use varied shaft sizes across a product line.

Japanese Agricultural Machinery

Japanese combine harvesters, rice transplanters and threshers — exported extensively to Southeast Asia, Australia and South Korea — use JIS chain throughout. NK35B and NK40B stock bore sprockets with small to medium tooth counts are the most common replacement items for Japanese agricultural machinery service. The NK bore range accommodates the metric shaft sizes used in all Japanese agricultural equipment.

Taiwanese & Chinese Industrial Plant

Taiwan, China and Southeast Asia all use JIS-based chain standards for industrial conveyor and machine drive applications. NK stock bore sprockets are the standard replacement parts specification for conveyors, elevators and process machinery manufactured in these regions. The NK bore range covers the metric shaft diameters (20–100 mm) used throughout Asian industrial machinery. See the categoria pignone completo.

Catena abbinata e prodotti correlati

JIS B1801 Asian standard roller chain 35B 40B 60B for NK stock bore sprockets

Matching Asian Standard Roller Chain

Match NK35B/NK40B/NK60B sprockets with JIS B1801 Asian standard roller chain of the corresponding size (35B, 40B, 60B). Standard and H-series variants available. Stainless SUS304 chain for food and washdown applications.

View Driving Chains →

Catene a balestra Ever-Power coreane per carrelli elevatori e paranchi

catene di foglie

Catene a maglie piatte serie BL e LH per montanti di carrelli elevatori, azionamenti per porte industriali e meccanismi di sollevamento. Portate di trazione da 11 kN a oltre 1.600 kN.

Visualizza le catene di foglie

Catene ingegneristiche Ever-Power coreane per il trasporto pesante

Catene ingegneristiche

Catene in acciaio saldato, ghisa e forgiate per il trasporto industriale pesante in acciaierie, cementifici, miniere e impianti chimici.

Visualizza le catene ingegneristiche

Catena a rulli in acciaio inossidabile Ever-Power coreana

Catene in acciaio inossidabile

Catene a rulli in acciaio inox SUS304 e SUS316L per ambienti alimentari, farmaceutici e chimici. Adatte a lavaggi frequenti, temperature elevate e agenti corrosivi.

Visualizza catene in acciaio inox

filiera agricola-1

Filiere agricole

Serie CA, CC e catene per mais per mietitrebbie, raccoglitrici di cotone, presse e spandiconcime. Conformi agli standard ISO 487 / ASME B29.100.

Visualizza le filiere agricole

 

 

Request a Quote — Asian Standard NK Stock Bore Sprockets

Specify chain size (e.g. NK40B), tooth count and required bore diameter in mm. Platewheel (DP type) available for all sizes. Keyway to JIS B1301. Response within one working day.

Informazioni aggiuntive

Redattore

Cxm

Prodotti correlati