{"id":260,"date":"2026-07-31T07:16:15","date_gmt":"2026-07-31T07:16:15","guid":{"rendered":"https:\/\/5speedtransmission.com\/?post_type=product&p=260"},"modified":"2026-07-31T07:16:15","modified_gmt":"2026-07-31T07:16:15","slug":"stock-bore-sprockets-platewheels-asian-standard","status":"publish","type":"product","link":"https:\/\/5speedtransmission.com\/es\/producto\/stock-bore-sprockets-platewheels-asian-standard\/","title":{"rendered":"Stock Bore Sprockets & Platewheels Asian Standard"},"content":{"rendered":"
\n

<\/p>\n

\n
\n

25B \u2013 120B<\/p>\n

Rango de tama\u00f1o de cadena<\/p>\n<\/div>\n

\n

NK Series<\/p>\n

Type NK & Platewheels<\/p>\n<\/div>\n

\n

Any Bore<\/p>\n

Machined to Specification<\/p>\n<\/div>\n

\n

JIS B1801<\/p>\n

Asian Standard<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Asian Standard Stock Bore Sprockets & Platewheels \u2013 Product Overview<\/h2>\n
\n
\n

The NK designation stands for the type hub used throughout the Asian standard sprocket series \u2014 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.<\/p>\n

In addition to standard toothed sprockets, this series also includes platewheels (DP type)<\/strong> \u2014 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.<\/p>\n<\/div>\n

\"Korea<\/p>\n
\n

\ud83d\udcd0 NK Hub Dimension Key<\/p>\n\n\n\n\n\n\n\n\n\n
Symbol<\/th>\nMeaning<\/th>\n<\/tr>\n
Do<\/td>\nTip (outside) diameter (mm)<\/td>\n<\/tr>\n
Dp<\/td>\nPitch circle diameter (mm)<\/td>\n<\/tr>\n
BD min<\/td>\nPilot bore diameter (mm)<\/td>\n<\/tr>\n
BD max<\/td>\nMaximum finished bore (mm)<\/td>\n<\/tr>\n
BL<\/td>\nHub bore length (mm)<\/td>\n<\/tr>\n
* prefix<\/td>\nMax bore with recessed hub groove for chain clearance<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n

<\/p>\n

\n

NK Stock Bore vs FBN Finished Bore \u2014 Which to Order?<\/h2>\n

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.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Situation<\/th>\nNK Stock Bore<\/th>\nFBN Finished Bore<\/th>\n<\/tr>\n<\/thead>\n
Shaft is a standard JIS bore size (e.g. 20, 22, 25 mm)<\/td>\n\u2714 Can be used<\/td>\n\u2714 Faster \u2014 arrives ready<\/strong><\/td>\n<\/tr>\n
Shaft is between standard sizes (e.g. 28 mm, 33 mm)<\/td>\n\u2714 Machine to exact size<\/strong><\/td>\n\u2716 Not available in that bore<\/td>\n<\/tr>\n
Non-standard tolerance required (H5, H6, interference fit)<\/td>\n\u2714 Machine to any tolerance<\/strong><\/td>\n\u2716 H7 only as standard<\/td>\n<\/tr>\n
Large Z count not in FBN range<\/td>\n\u2714 Full Z range available<\/strong><\/td>\n\u2716 Limited to catalogue bores<\/td>\n<\/tr>\n
Platewheel (solid disc) required<\/td>\n\u2714 DP platewheel variant<\/strong><\/td>\n\u2716 Not available<\/td>\n<\/tr>\n
No machining facility on site<\/td>\n\u2716 Requires lathe<\/td>\n\u2714 Ready to fit<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

<\/p>\n

NK Stock Bore Sprocket Specifications \u2014 35B through 60B<\/h2>\n

NK35B \u00a0|\u00a0 Pitch 9.525 mm \u00a0|\u00a0 Roller \u00d8 5.08 mm \u00a0|\u00a0 Inner width 4.78 mm<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n
Z<\/th>\nDo (mm)<\/th>\nDp (mm)<\/th>\nBD min (mm)<\/th>\nBD max (mm)<\/th>\nBL (mm)<\/th>\n<\/tr>\n<\/thead>\n
9<\/td>\n32<\/td>\n27.85<\/td>\n9.5<\/td>\n*21.5<\/td>\n20<\/td>\n<\/tr>\n
12<\/td>\n41<\/td>\n36.81<\/td>\n9.5<\/td>\n*30.5<\/td>\n20<\/td>\n<\/tr>\n
17<\/td>\n57<\/td>\n51.84<\/td>\n11.5<\/td>\n41<\/td>\n20<\/td>\n<\/tr>\n
25<\/td>\n81<\/td>\n76.00<\/td>\n11.5<\/td>\n57<\/td>\n20<\/td>\n<\/tr>\n
36<\/td>\n114<\/td>\n109.08<\/td>\n11.5<\/td>\n62<\/td>\n20<\/td>\n<\/tr>\n
57<\/td>\n176<\/td>\n172.91<\/td>\n11.5<\/td>\n67<\/td>\n20<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

NK40B \u00a0|\u00a0 Pitch 12.70 mm \u00a0|\u00a0 Roller \u00d8 7.92 mm \u00a0|\u00a0 Inner width 7.85 mm<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n
Z<\/th>\nDo (mm)<\/th>\nDp (mm)<\/th>\nBD min (mm)<\/th>\nBD max (mm)<\/th>\nBL (mm)<\/th>\n<\/tr>\n<\/thead>\n
9<\/td>\n42<\/td>\n37.13<\/td>\n8.5<\/td>\n*28<\/td>\n22<\/td>\n<\/tr>\n
12<\/td>\n55<\/td>\n49.07<\/td>\n11.5<\/td>\n*40<\/td>\n22<\/td>\n<\/tr>\n
15<\/td>\n67<\/td>\n61.09<\/td>\n13.5<\/td>\n*46<\/td>\n22<\/td>\n<\/tr>\n
17<\/td>\n76<\/td>\n69.12<\/td>\n13.5<\/td>\n54<\/td>\n22<\/td>\n<\/tr>\n
25<\/td>\n108<\/td>\n101.33<\/td>\n13.5<\/td>\n70<\/td>\n22<\/td>\n<\/tr>\n
38<\/td>\n158<\/td>\n153.80<\/td>\n13.5<\/td>\n80<\/td>\n22<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

NK60B \u00a0|\u00a0 Pitch 19.05 mm \u00a0|\u00a0 Roller \u00d8 11.91 mm \u00a0|\u00a0 Inner width 12.70 mm<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n
Z<\/th>\nDo (mm)<\/th>\nDp (mm)<\/th>\nBD min (mm)<\/th>\nBD max (mm)<\/th>\nBL (mm)<\/th>\n<\/tr>\n<\/thead>\n
9<\/td>\n63<\/td>\n55.70<\/td>\n11.5<\/td>\n*43<\/td>\n32<\/td>\n<\/tr>\n
13<\/td>\n89<\/td>\n79.06<\/td>\n14<\/td>\n57<\/td>\n32<\/td>\n<\/tr>\n
17<\/td>\n113<\/td>\n103.67<\/td>\n16<\/td>\n73<\/td>\n32<\/td>\n<\/tr>\n
21<\/td>\n139<\/td>\n127.82<\/td>\n16<\/td>\n83<\/td>\n40<\/td>\n<\/tr>\n
25<\/td>\n165<\/td>\n152.00<\/td>\n16<\/td>\n90<\/td>\n40<\/td>\n<\/tr>\n
38<\/td>\n237<\/td>\n230.78<\/td>\n16<\/td>\n100<\/td>\n40<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

* = max bore with hub groove for chain clearance. NK25B, NK50B, NK80B, NK100B and NK120B also available \u2014 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.<\/p>\n

<\/p>\n

\"\"<\/p>\n
\n

Caracter\u00edsticas t\u00e9cnicas<\/h2>\n
\n
\n

Recessed Hub Groove (* Max Bore)<\/h3>\n

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 \u2014 exceeding it removes the minimum hub wall required for the groove and for the setscrew thread.<\/p>\n<\/div>\n

\n

Platewheels \u2014 DP Type<\/h3>\n

Platewheels (DP type) are solid ring sprockets without a traditional hub \u2014 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.<\/p>\n<\/div>\n

\n

Full Tooth Count Flexibility<\/h3>\n

The NK stock bore range covers tooth counts from Z=9 to Z=114 for most chain sizes \u2014 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 \u2014 non-catalogue tooth counts can also be produced on order.<\/p>\n<\/div>\n

\n

JIS B1801 Tooth Profile<\/h3>\n

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<\/a> of the matching chain size designation. Remember: 40B chain requires NK40B sprocket, not #40 ANSI sprocket or 08B European sprocket \u2014 the roller diameters differ between standards even at the same pitch.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

<\/p>\n

\n
\n

Korean OEM Industrial Equipment<\/h3>\n

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.<\/p>\n<\/div>\n

\n

Japanese Agricultural Machinery<\/h3>\n

Japanese combine harvesters, rice transplanters and threshers \u2014 exported extensively to Southeast Asia, Australia and South Korea \u2014 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.<\/p>\n<\/div>\n

\n

Taiwanese & Chinese Industrial Plant<\/h3>\n

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\u2013100 mm) used throughout Asian industrial machinery. See the categor\u00eda de pi\u00f1ones completos<\/a>.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Cadena a juego y productos relacionados<\/h2>\n
\"JIS<\/p>\n
\n

Matching Asian Standard Roller Chain<\/p>\n

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.<\/p>\n

View Driving Chains \u2192<\/a><\/p>\n<\/div>\n<\/div>\n

\n
\n

\"Korea<\/p>\n

Cadenas de hojas<\/a><\/h3>\n

BL and LH series leaf chains for forklift masts, industrial door drives, and hoist mechanisms. Tensile ratings from 11 kN to over 1,600 kN.<\/p>\n

Ver cadenas de hojas<\/a><\/p>\n<\/div>\n

\n

\"Korea<\/p>\n

Cadenas de ingenier\u00eda<\/a><\/h3>\n

Welded steel, cast iron, and forged chains for heavy-duty industrial conveying in steel mills, cement plants, mining, and chemical processing.<\/p>\n

Ver cadenas de ingenier\u00eda<\/a><\/p>\n<\/div>\n

\n

\"Korea<\/p>\n

Cadenas de acero inoxidable<\/a><\/h3>\n

SUS304 and SUS316L roller chains for food, pharmaceutical, and chemical environments. Suitable for washdown, elevated temperature, and corrosive media.<\/p>\n

Ver cadenas de acero inoxidable<\/a><\/p>\n<\/div>\n

\n

\"cadena-agr\u00edcola-1\"<\/p>\n

Cadenas agr\u00edcolas<\/a><\/h3>\n

CA, CC, and corn-chain series for combine harvesters, cotton pickers, balers, and spreading equipment. ISO 487 \/ ASME B29.100 standard.<\/p>\n

Ver cadenas agr\u00edcolas<\/a><\/p>\n<\/div>\n

\u00a0<\/a><\/p>\n

 <\/p>\n<\/div>\n

<\/p>\n

\"\"<\/p>\n
\n

Request a Quote \u2014 Asian Standard NK Stock Bore Sprockets<\/h3>\n

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.<\/p>\n

Obt\u00e9n un presupuesto ahora<\/a>
\nTodos los productos de pi\u00f1ones<\/a><\/div>\n<\/div>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power Asian standard stock bore sprockets (NK series) are the unfinished-bore version of the Asian standard range \u2014 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.<\/p>","protected":false},"featured_media":243,"comment_status":"open","ping_status":"closed","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[24],"product_tag":[],"class_list":["post-260","product","type-product","status-publish","has-post-thumbnail","product_cat-sprockets","first","instock","shipping-taxable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/product\/260","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/comments?post=260"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/media\/243"}],"wp:attachment":[{"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/media?parent=260"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/product_brand?post=260"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/product_cat?post=260"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/5speedtransmission.com\/es\/wp-json\/wp\/v2\/product_tag?post=260"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}