31-XG-BD-EC Rotor Complete
Standard-profile rotor complete for everyday cotton counts (Ne 16–40) on the Rieter R40 fully automatic platform. BD two-layer build: hardened substrate, diamond face. Dimensionally identical to the original part and supplied at 40–60% below OEM price, with balancing verified on our own line.
31-XG-BD-EC — Complete Specifications
All measurements in millimetres. Every rotor complete assembly is 100% dynamically balanced on our own balancing line before shipment.
Why XG Groove for Everyday Cotton Spinning
The G groove aims at the everyday middle of a mill’s count schedule, where cotton in the Ne 16–40 band needs a stable fibre ring more than it needs the extremes of the range. Rotors in this group share that groove and differ by cup diameter, so the groove can stay constant while the count moves.
XG Groove — Applicable Yarn Count Range
Medium counts are the design point. If the schedule drifts below Ne 16, plan for the U or GL groove rather than stretching this one. Send us the fibre type and target count with the enquiry and we confirm the pairing.
XG Groove — Built for the Middle of the Count Range
The standard G groove is sized for the fibre mass of medium counts, so fibre collection, twist propagation and yarn formation all sit in the comfortable part of the curve. End-break behaviour stays flat across a full doff. It is the specification to fall back on when a mill wants one groove for the bulk of its cotton schedule.
Cost-Effective Standard
The G rotor is the workhorse of the range — a straightforward coated cup for mills where cost per kilogram of yarn and steady running both matter.
Matched to Ne 16–40
The groove volume is sized for the fibre mass of 16–40 Ne cotton, so fibre collection stays in the stable part of the curve across the whole band.
Even Yarn, Run to Run
A medium-width deposition zone holds the fibre ring steady between doffs, which is what keeps count and appearance consistent in routine production.
Fewer End Breaks
Twist propagation through a standard-profile groove avoids the tension spikes that appear when a rotor is pushed outside its count band.
What BD 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. This code is a two-layer build: B puts a boronized (boron-steel) substrate under the film, D is the diamond top layer. The base is what stops fibre impact from deforming the rotor and cracking the coating. The rotor is dimensionally identical to the original part, so no machine modification is needed.
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.
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 31-XG-BD-EC?
The R40-EC bearing locks this rotor to the Rieter R40 platform. Rotors from a different bearing group will not interchange, however similar the cup looks.
What to Spin with 31-XG-BD-EC
Typical operating profile for the XG groove on the Rieter R40 fully automatic platform. Groove count windows follow the catalogue data.
✓ Cotton and cotton-rich blends, medium to fine counts
✓ Ne 16–40 — the mainstream of a cotton spinning schedule
✓ Carded and combed cotton on fully automatic platforms
◇ Coarse counts Ne 3–16 — GL groove, large-diameter rotors
◇ Abrasive or high-impurity fibre — specify DN diamond coating
◇ Fine counts at the top of the band — XT / XTC narrow family
→ U: General purpose (Ne 10–30)
→ GL: Large (Ne 3–16)
→ G: Standard (Ne 16–40) — this model
→ T: Narrow (Ne 16–40)
→ TT: Extra narrow (Ne 16–40)
→ See all 4 Rieter R40 rotor models →
31-XG-BD-EC — 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 31-XG-BD-EC compatible with my Rieter R40 machine?
What does the model code 31-XG-BD-EC mean?
What yarn counts does the XG groove suit?
What do the letters BD mean in the model code 31-XG-BD-EC?
How much does an OEM-equivalent rotor save versus the original?
Can I order the rotor spindle or rotor cup separately?
Order 31-XG-BD-EC Rotors
Pre-filled: 31-XG-BD-EC · Rieter R40 · boronized base + diamond coating
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