OS21DN Solid Ring — OS21 (S21) Tooth Profile Clothing Ring
One-piece clothing ring in the OS21 tooth profile (also designated S21) with a DN diamond-nickel working surface (HV 1000-1200). The synthetic-fibre profile in the range — polyester, viscose, acrylic and P/C blends open cleanly on a tooth form built for abrasive fibre.
OS21DN — Complete Specifications
OS21 is the S21 tooth type under JSM’s opening-roller designation. Both names describe the same profile — quote whichever your catalogue uses and we will match it.
Why OS21 for Synthetic Fibre Programmes
OS21 is the synthetic-fibre profile in the JSM solid ring range — the same tooth type sold elsewhere as S21. Polyester, acrylic and P/C blends are abrasive on a cotton-oriented tooth form; OS21 is cut for them, and with the DN diamond-nickel surface it keeps its edge instead of polishing away.
The profile that lets the S-series run polyester without eating rings
Synthetic fibre is abrasive in a way cotton is not: it wears the tooth tips back until the band stops opening the sliver consistently, and that arrives as rising yarn CV% long before anything looks worn. OS21 pairs a tooth form cut for synthetic staple with a DN diamond-nickel working surface, which is the combination that keeps the profile stable across a synthetic campaign.
Synthetic-oriented tooth cut
Tooth geometry set for polyester, viscose, acrylic and P/C blends — the profiles that struggle on a cotton-oriented band.
DN diamond-nickel surface
HV 1000-1200. Diamond co-deposited in a nickel matrix — the abrasive-fibre case the coating exists for.
One-piece concentricity
Ring and tooth band machined as a single part, so the profile runs true at high combing roller speed.
Cotton-compatible too
Cotton and cotton-rich blends run acceptably on OS21, so a mill switching between synthetic and cotton campaigns can keep one profile on the shelf.
What DN Means on a JSM Solid Ring
Every ring in this range carries a DN working surface: diamond grit co-deposited inside a nickel matrix, HV 1000-1200. The earlier plain-nickel tooth types have been withdrawn — catalogue numbers ending in N are no longer produced or quoted.
Diamond grit is co-deposited inside a nickel matrix rather than simply plated on top. The result is a hard, low-friction working surface that holds its tooth form far longer than plain nickel on abrasive fibre, keeps the tooth tips from loading up with fibre and dust, and holds concentricity across a longer service interval.
The earlier plain-nickel tooth types are no longer produced, and catalogue numbers ending in N are not quoted. Order the DN version of the same tooth profile instead: identical tooth geometry and fit, with the diamond-nickel working surface. If you are holding stock of an N-type ring, send us the number and we will cross it to the current DN equivalent.
Which Machines Use OS21DN?
The same tooth profile is supplied in both machine platforms. The part number differs, so quote your machine model with the enquiry and we supply the matching configuration.
Running Taitan, Jingwei, Rifa or Saurer machines? The solid ring range in this catalogue is built for the Schlafhorst and Rieter platforms listed above, so we will not claim it fits a machine we have not checked. Send us the machine model and the part you are replacing and we will confirm whether a ring from this range fits, or supply the correct opening-roller component.
What to Spin with OS21DN
OS21 is the synthetic-side profile. Match it to the fibre, not to the machine brand — the same tooth type is supplied in a Schlafhorst and a Rieter NG64 configuration.
All 7 Tooth Profiles — Where OS21DN Sits
Every profile in the range is DN coated and covers Schlafhorst Autocoro SE8–SE20. B-series profiles are cotton and natural-fibre oriented, S-series profiles are built for synthetics. Your current model is highlighted.
| Tooth Profile | Coating | Fibre Direction | Page |
|---|---|---|---|
| B174 / B174-2 | DN | Carded cotton and flax blends (best); combed cotton, viscose (OK); not for P/C or synthetic blends | View page |
| B187 | DN | Combed cotton, viscose (best); blends (OK); not for carded cotton, acrylic or flax | On request |
| B300 | DN | Newer tooth type — application data under confirmation | View page |
| OB20 (B20) | DN | Carded and combed cotton, flax blends (best); viscose (OK); not for pure synthetic fibres | View page |
| OS21 (S21) | DN | Polyester, viscose, acrylic and P/C blends (best); cotton (OK); not for flax | View page |
| S43 | DN | Polyester, P/C and P/V blends (best); not for cotton, viscose, acrylic or flax | On request |
| OK61 | DN | Newer tooth type — application data under confirmation | On request |
Rieter R40 / R60 / R66 machines take the same tooth profile in a separate NG64 configuration. It is not interchangeable with the Schlafhorst ring even though the tooth geometry looks identical, so quote your machine model with the enquiry and we will supply the matching configuration.
B-series tooth types suit cotton and natural fibres; S-series tooth types suit synthetics. Where a profile needs its fibre recommendation confirmed against your own schedule we say so rather than publish a general claim. Not sure which profile you are running? Send a photo of the worn ring and the machine model and we will identify it.
OS21DN — Frequently Asked Questions
The questions mills ask most often about this ring. Anything not covered here, ask directly — we answer with the part number and the price, not a brochure.
What is the difference between OS21 and S21?
Which machines does OS21DN fit?
What fibres does OS21DN suit best?
What does DN mean?
My programme mixes polyester and cotton. Which ring should I hold?
Send Us Your Machine Model and Fibre Mix
Pre-filled: OS21DN · OS21 tooth profile
Tell us your machine model, the ring position and your fibre mix. We confirm the profile, price and lead time within 24 hours. Sample orders welcome.
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