40-S-D Rotor Complete
Special-profile rotor complete for blends and speciality fibres (Ne 16–40) on the Rieter R1, R20, R40 and R60 fully automatic platform. Diamond top layer on the prepared substrate. Every assembly is dynamically balanced and vibration-checked before shipment, at 40–60% below the OEM part price.
40-S-D — Complete Specifications
All measurements in millimetres. Every rotor complete assembly is 100% dynamically balanced on our own balancing line before shipment.
Why S Groove for Blends and Speciality Fibres
Blends change everything about fibre guidance — different fibre lengths, different friction. The S groove is shaped for that mix, inside the Ne 16–40 band. Bearing fit is unchanged across the group — only the groove profile and cup size distinguish the models.
S Groove — Applicable Yarn Count Range
Aimed at mixed fibre. For 100% cotton at the same counts the G or T groove is the simpler choice. Coating grade and count band are confirmed with the quotation for this rotor.
S Groove — For Mixes a Cotton Profile Handles Poorly
Speciality fibres do not deposit like cotton. The S groove is designed around that difference, holding a mixed fibre ribbon steady so yarn properties stay inside specification across the count band. Mills running several fibre types often keep an S-profile rotor alongside their standard cotton rotors.
Consistent Blend Yarn
Keeps yarn strength and appearance steady when the blend ratio or the fibre supplier changes.
Fewer Blend-Related Faults
Guides the mixed ribbon so the longer component does not run ahead and create faults.
Uniform Yarn Face
Even distribution of dissimilar fibres gives a more uniform yarn surface.
Tolerant of Lot Variation
Designed to absorb the variation that comes with buying speciality fibre lot by lot.
What D Means: Base and Working Surface
The trailing letters of the model code are two independent codes, not one word: B is the substrate, D is the working surface. The diamond face is the reason this rotor holds its groove profile on long runs. Confirm your fibre mix and speed with us before a bulk order. Ordering rotors, bearings and opening rollers together keeps freight and coating consistent across the spin box.
B = boronized (boron-steel) substrate. A diamond film is only microns thick, so the steel underneath decides whether it survives: a soft substrate deforms under fibre and grit impact and the film cracks and spalls off. The boronized base is the hardening step that keeps the diamond layer intact. This code does not carry the B step; it is the -BD- variant that pairs the diamond layer with the boronized base.
D = diamond top layer, grown on the prepared substrate as a micron-scale film. It takes the fibre and grit contact directly, which is where the wear resistance, the friction coefficient of 0.05–0.1 and the anti-stick behaviour come from that hold the groove profile over long runs. Diamond coating technology of US origin, applied on JSM’s own treatment line.
Which Rieter Machines Use 40-S-D?
The R20 Twin Disc bearing is the rotor standard across the Rieter R1, R20, R40 and R60 series, so this group is the one to specify for any of the four machines.
What to Spin with 40-S-D
Application guidance for 40-S-D on the fully automatic side of the Rieter range; counts and fibre types follow the S groove specification.
✓ Polyester-cotton and multi-component blends
✓ Mills buying speciality fibre lot by lot
✓ Yarns where blend consistency is judged downstream
◇ Coarse counts Ne 3–16 — GL groove
◇ Abrasive blends — DN diamond coating
◇ 100% commodity cotton — G standard groove
→ G: Standard (Ne 16–40)
→ T: Narrow (Ne 16–40)
→ TT: Extra narrow (Ne 16–40)
→ S: Special (Ne 16–40) — this model
→ U: General purpose (Ne 10–30)
→ See all 6 Rieter R1, R20, R40 and R60 rotor models →
40-S-D — Frequently Asked Questions
Answers to the questions buyers ask most often about this rotor. If yours is not listed, send it with your machine model and current rotor code — we reply within 24 hours.
Is 40-S-D compatible with my Rieter R1, R20, R40 and R60 machine?
What does the model code 40-S-D mean?
What yarn counts does the S groove suit?
What do the letters BD mean in the model code 40-S-D?
How much does an OEM-equivalent rotor save versus the original?
Can I order the rotor spindle or rotor cup separately?
Order 40-S-D Rotors
Pre-filled: 40-S-D · Rieter R1 / R20 / R40 / R60 · diamond coating
Tell us your quantity and we respond with pricing, lead time and freight options within 24 hours. Sample orders welcome.
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