SIZE REFERENCE / YZEFY SPROCKETS
20B sprockets
20B sprockets are selected for European industrial drives, conveyors, material handling and heavy equipment. The 20B designation identifies the ISO 606 B-series chain family, but it does not finish the sprocket specification. Confirm strand, teeth, bore, keyway, hub and available axial space before ordering. 20B requests usually need the chain dimensions plus a clear drawing of the larger bore, hub and tooth arrangement.
A standard request can start with the chain marking and required tooth count. A custom or replacement request should include the applicable drawing, sample, measured sprocket or shaft information. The chain and the shaft interface need to be checked as one assembly.
Size reference
20B Sprockets
- SpecificationReference
- Chain referenceISO 606 20B
- SeriesB-series
Quick Specifications
| Specification | Reference |
|---|---|
| Chain reference | ISO 606 20B |
| Series | B-series |
| Pitch | 31.750 mm |
| Roller diameter | 19.050 mm |
| Inner width | 19.560 mm |
| Strand | Simplex, duplex or triplex, stated in the complete chain designation |
| Sprocket forms | Type A plate, Type B hub, Type C double hub and drawing-defined forms |
| Bore and hub | Pilot or finished bore, keyway, bushing or custom shaft interface |
Chain & Size Reference
These values identify the mating chain. They are not finished sprocket dimensions. Pitch diameter, outside diameter, tooth width, bore and hub dimensions depend on the tooth count, strand arrangement and machine drawing.
| Chain | Series | Pitch (mm) | Roller diameter (mm) | Inner width (mm) |
|---|---|---|---|---|
| 20B | B | 31.750 | 19.050 | 19.560 |
Simplex / Duplex / Triplex
A simplex sprocket carries one chain row. Duplex and triplex versions carry two or three rows and use different transverse spacing and total tooth width. Include the full strand suffix with 20B. The base designation alone is not enough for a multi-strand part.
Available Sprocket Configurations
- Type A plate sprockets for compact layouts or separate-hub assemblies.
- Type B sprockets with a hub on one side.
- Type C sprockets with hubs on both sides or a wider shaft interface.
- Idler, split, weld-on, bushing-mounted and other drawing-defined forms.
Do not assign a tooth count from the chain size alone. Confirm driver and driven teeth in the RFQ or drawing.
Materials
Carbon steel is used for many general industrial drives. Alloy steel can be considered for higher load, shock or wear requirements. Stainless steel suits corrosion, washdown and cleaning exposure. Cast iron, aluminum and engineering plastics may fit specific low-load or weight-sensitive designs. State the material grade, supply condition and certificate requirement in the RFQ.
Heat Treatment & Surface Treatment
Tooth hardening, induction hardening or carburizing may be specified when the drawing or application requires greater tooth wear resistance. Protective surface treatment can be considered for corrosion, storage or washdown conditions. Include hardness, case depth, treated area, surface finish and inspection method when those values are controlled by the purchase specification.
Custom 20B Sprockets
Send the ISO series, chain reference, number of teeth, strand, bore, keyway, hub dimensions and quantity. Add material, heat treatment, surface treatment, tolerances, marking and inspection requirements from the drawing. For sample-based work, include the chain marking, tooth count, pitch, roller diameter, inner width, face width and shaft measurements. Application speed, load, center distance and operating environment can resolve details that a worn sample cannot show.
Replacement Sprockets
A replacement 20B sprocket should be checked against the mating chain and shaft, not copied from worn tooth tips. Send the old chain marking, tooth count, bore, keyway, hub, face width, photos and any part number. If the failure involved chain elongation, poor alignment, inadequate lubrication or contamination, inspect the chain and mating sprocket before replacing one part.
Applications
20B sprocket requests commonly come from European industrial drives, conveyors, material handling and heavy equipment. The application helps define the review, but it does not choose the tooth count or shaft connection. Load, speed, chain line, environment and mounting space still belong in the specification.
Standard & Compatibility Notes
20B is a B-series reference used in ISO-related DIN and BS documentation. It should not be matched to an A-series or ANSI number by pitch alone. The series suffix must stay in every RFQ and drawing. Compare pitch, roller diameter, inner width, strand spacing, tooth form and shaft interface before approving a substitute.
How to Select
- Confirm ISO 606, the B-series suffix and the complete 20B chain reference.
- State simplex, duplex or triplex and the complete strand suffix.
- Record driver and driven teeth, speed ratio, center distance and chain line.
- Check pitch, roller diameter, inner width and transverse spacing.
- Select Type A, Type B, Type C or another drawing-defined form.
- Specify bore, keyway, locking method, hub dimensions and axial clearance.
- Add material, treatment, finish, quantity, inspection and drawing revision.
- Send a sample or measured photo if any original dimension is uncertain.
FAQ
What are the 20B chain dimensions?
The reference row lists a 31.750 mm pitch, 19.050 mm roller diameter and 19.560 mm inner width.
Does 20B define a standard bore?
No. Bore, keyway, hub and locking method are machine-interface fields.
Can an old 20B sprocket be reproduced?
A drawing, chain marking, tooth count, shaft measurements and sample can start a replacement review.
What is the canonical 20B page?
This ISO B-series page is the shared child record for ISO, DIN and BS navigation.
Request a Quote for 20B Sprockets
Send the ISO series, chain reference, number of teeth, strand, bore, keyway, hub, quantity and application. For custom or replacement work, attach the drawing, sample photo, old sprocket dimensions or existing part number. This prevents a shared-pitch comparison from being treated as a complete fit confirmation.