Metric Planetary Roller Screw Assembly, with One Piece Flanged Nut and without Wipers, 8x4


One-piece solid nuts do not have a calibrated spacer to remove backlash. One-piece nuts have larger load ratings since all threads of the nut can carry load.


NRS planetary roller screws are made of high strength materials. The screw shaft is made of medium carbon induction hardenable alloy steel. The rollers and nut are manufactured from high grade bearing steel. All rolling surfaces are heat treated to a surface hardness not less than 56 HRC with a case depth suitably chosen to carry the load. Other materials, such as stainless steel, can be provided upon request.

Reduced load ratings should be considered when designing stainless steel roller screws.

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Product NRS BF NW 8x4
Product Info
Nominal Rod Diameter [mm] 8
Lead [mm] 4
End Code for Types 1,2,3,5 [* Journals may show tracings of the thread] n/a
D1 [mm] 21
D4 [mm] 31
D6 [mm] 41
D7 M4
D8 [mm] -
L1 [mm] 41
L3 [mm] 13
L4 [mm] 14
n x D5 6x4.5
Performance Specifications
Backlash [mm] 0.02
Dynamic Load Ratings Ca [kN] 5.43
Static Load Ratings Coa [kN] 18.63

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