STANDARD REFERENCE / YZEFY SPROCKETS
JIS sprockets
JIS sprockets are used with Japanese Industrial Standard roller chains and Japanese equipment drawings. They appear in Japanese-designed machinery, automation, packaging equipment, conveyors, OEM systems and industrial replacement work. JIS B 1801 includes A-series and B-series chain families, so the series and complete chain reference matter as much as the pitch. Confirm strand count, number of teeth, bore, keyway and hub before ordering. For a custom or replacement sprocket, send the Japanese drawing, chain marking, old sprocket, photo, sample or measured dimensions with the quantity and application.
Standard reference
JIS Sprockets
- SpecificationDetails
- Standard referenceJIS B 1801:2020 for short-pitch transmission precision roller and bush chains
- JIS chain familiesA series, A-series H and HE classes, and B series
Quick Specifications
| Specification | Details |
|---|---|
| Standard reference | JIS B 1801:2020 for short-pitch transmission precision roller and bush chains |
| JIS chain families | A series, A-series H and HE classes, and B series |
| Common A-series references | 25, 35, 40, 50, 60 and 80, often marked RS25 through RS80 by chain suppliers |
| Common B-series references | 06B, 08B, 10B and 12B |
| Strand | Simplex, duplex and triplex where the chain designation and transverse spacing permit |
| Sprocket forms | Type A plate, Type B hub, Type C double hub, separated hub and drawing-defined forms |
| Bore options | Pilot bore, finished bore, keyed bore, bushing interface and custom shaft interface |
| Selection basis | JIS series, chain dimensions, teeth, strand spacing, bore, keyway, hub and drawing revision |
Available Sizes
JIS A-series child links use the matching ANSI size pages. Selected JIS B-series links use the shared ISO B-series pages.
A-series and RS references
B-series
Chain & Size Reference
The table gives common JIS dimensions in millimetres for a first chain and sprocket fit review. The A-series rows use common JIS or RS market markings. For 25 and 35, the listed diameter is the bush diameter used by the relevant chain family rather than a separate rotating roller. The B-series rows show the selected B-family references. Confirm the exact JIS drawing and supplier marking before releasing a replacement drawing.
| JIS chain reference | Series | Pitch | Roller or bush diameter | Inner width |
|---|---|---|---|---|
| 25 or RS25 | A | 6.350 | 3.300 | 3.180 |
| 35 or RS35 | A | 9.525 | 5.080 | 4.780 |
| 40 or RS40 | A | 12.700 | 7.920 | 7.950 |
| 50 or RS50 | A | 15.875 | 10.160 | 9.530 |
| 60 or RS60 | A | 19.050 | 11.910 | 12.700 |
| 80 or RS80 | A | 25.400 | 15.880 | 15.880 |
| 06B | B | 9.525 | 6.350 | 5.720 |
| 08B | B | 12.700 | 8.510 | 7.750 |
| 10B | B | 15.875 | 10.160 | 9.650 |
| 12B | B | 19.050 | 12.070 | 11.680 |
The same pitch can appear in different JIS series with different roller or bush geometry and inner width. Pitch diameter, outside diameter, tooth width, bore and hub are sprocket dimensions that still depend on the tooth count and machine drawing.
Available Sprocket Configurations
Sprocket forms
- Type A plate sprockets for hubless or separately mounted arrangements.
- Type B sprockets with a hub on one side.
- Type C sprockets with hubs on both sides or a wider shaft interface.
- Separated-hub, idler, split, weld-on, bushing-mounted and other drawing-defined forms.
Strand configurations
Specify simplex, duplex or triplex and include the complete chain suffix. The sprocket must match the JIS series and the transverse spacing between chain rows. A JIS 40 or RS40 marking does not by itself define a duplex or triplex sprocket.
Materials
Carbon steel is common for general JIS transmission and conveyor drives. Alloy steel can be considered for higher load, shock or tooth wear. Stainless steel suits corrosion, washdown and cleaning exposure. Cast iron, aluminum and engineering plastics may be considered for application-specific low-load or weight-sensitive designs.
State the material grade, supply condition and certificate requirement in the RFQ. Choose material against load, speed, shock, lubrication, temperature, corrosion and cleaning conditions, not only the machine’s country of origin.
Heat Treatment & Surface Treatment
Tooth hardening and induction hardening can address repeated tooth wear. Carburizing may be specified for a hard case and tougher core when required by the drawing. Protective surface treatment can be considered for corrosion, storage or washdown conditions.
Include hardness, case depth, treated area, surface finish and inspection method when the JIS drawing controls them. If the original drawing does not state a treatment, provide load cycle, speed, lubrication and environment for review with the material and tooth geometry.
Custom JIS Sprockets
Custom JIS sprockets are defined by the JIS series, complete chain reference and machine interface. Send the standard number and revision, chain size, number of teeth, strand, bore, keyway, hub dimensions and quantity. Add material, treatment, tolerances, marking and inspection requirements from the Japanese drawing.
For an OEM order, include the drawing revision and mating chain reference. For a sample-based order, add photos, tooth count, pitch, roller or bush diameter, inner width, face width and shaft measurements. Application speed, load and center distance help resolve details missing from a worn sample.
Replacement Sprockets for Japanese Machinery
Replacement JIS sprockets are used for Japanese machines, old Japanese drawings, obsolete sprockets and MRO work where the original chain reference must be preserved. Send the Japanese drawing, machine model reference, JIS chain marking, tooth count, bore, keyway, hub, photos and sample details.
JIS B 1801:2020 is related to ISO 606:2015 but marked MOD. A similar ISO or ANSI marking is not enough to authorize a replacement. Compare the chain series, dimensions, tooth form, transverse spacing and shaft interface before selecting a substitute.
Applications
JIS sprocket inquiries commonly come from Japanese machinery, automation, packaging equipment, Japanese OEM systems, conveyors and industrial replacement programs. They also arise when an overseas maintenance team has a Japanese drawing but no current supplier part number.
The machine origin helps locate the right document family. The final sprocket still depends on the JIS series, chain dimensions, teeth, strand spacing, bore, keyway and hub.
Standard & Compatibility Notes
JIS B 1801:2020 is the Japanese standard for short-pitch transmission precision roller chains and bush chains. The standard divides chain types into A series, A-series H and HE classes, and B series. The associated sprocket provisions use the chain geometry, tooth form, tooth width and runout requirements needed for the selected chain family.
JIS B 1801:2020 corresponds to ISO 606:2015 with a MOD relationship. MOD means that the Japanese standard is based on the international standard but includes technical modifications. Therefore, JIS, ISO A-series, ISO B-series and ANSI-derived markings must be compared by complete dimensions and the applicable drawing.
How to Select
- Record JIS B 1801 and the standard revision shown on the drawing.
- Identify the A, A H, A HE or B series and the complete chain reference.
- Confirm pitch, roller or bush diameter, inner width and transverse spacing.
- Record driver and driven teeth, speed ratio, center distance, wrap and chain line.
- Select Type A, Type B, Type C or another drawing-defined form.
- Specify bore, keyway, bushing, hub, material, treatment and inspection.
- Attach the Japanese drawing, catalogue reference or sample for replacement work.
FAQ
What is JIS B 1801?
JIS B 1801:2020 specifies short-pitch transmission precision roller chains and bush chains, including A-series, strengthened A-series classes and B-series references with associated sprocket information.
Are JIS and ISO sprockets the same?
Not automatically. JIS B 1801:2020 is based on ISO 606:2015 but marked MOD, so technical modifications exist. Use the complete JIS designation and actual dimensions.
What does MOD mean?
MOD means that the Japanese standard is based on the international standard but contains technical modifications. It is not an unmodified identical adoption.
Can an ISO sprocket replace a JIS sprocket?
Only after the chain series, dimensions, tooth form, strand spacing and shaft interface have been compared. A shared pitch or similar number is not enough.
How do I identify a sprocket from Japanese machinery?
Send the JIS or RS chain marking, tooth count, bore, keyway, hub, face width, shaft details and photos. The original Japanese drawing or a matching chain sample improves identification.
Can a JIS sprocket be reproduced from a drawing or sample?
Yes. Include the JIS standard and revision, chain reference, teeth, bore, keyway, hub, material, treatment, quantity and the drawing or sample details.
Request a Quote for JIS Sprockets
Send the JIS standard reference, complete chain designation, series, strand count, number of teeth, bore, keyway, hub, quantity and application. Attach the Japanese drawing, machine reference, sample photo or measured existing sprocket for custom and replacement work.