$484.53 ea
Quantity Price (USD)
1 $484.53 ea
10 $363.40 ea
25 $271.34 ea
50 $162.92 ea
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In Production Lead Time: 0-2 Days
Ruland FCMR38-20-10-SS, 20mm x 10mm Six Beam Coupling, Stainless Steel, Clamp Style, 38.1mm OD, 57.2mm Length


Ruland FCMR38-20-10-SS is a six beam coupling with 20mm x 10mm bores, 38.1mm OD, and 57.2mm length. It is machined from a single piece of material and features two sets of three spiral cuts. This gives it higher torque capacity, lower windup, and larger body sizes than single or four beam couplings and allows for use in light duty power transmission applications such as coupling a servo motor to a lead screw. FCMR38-20-10-SS is zero-backlash and has a balanced design for reduced vibration at high speeds of up to 6,000 RPM. Ruland supplies this spiral coupling with Nypatch® anti-vibration hardware that allows for even seating of the screw, repeated screw installations, prevents galling, and maintains high holding power. All hardware is metric and tests beyond DIN 912 12.9 standards for maximum torque capabilities. FCMR38-20-10-SS is made from 303 stainless steel for increased torque capacity. It is machined from bar stock that is sourced exclusively from North American mills and RoHS2 and REACH compliant. FCMR38-20-10-SS is manufactured in our Marlborough, MA factory under strict controls using proprietary processes.



Large Bore B1

20 mm

Small Bore B2

10 mm

B1 Shaft Penetration

27.3 mm

B2 Shaft Penetration

27.3 mm

Outer Diameter OD

38.1 mm

Bore Tolerance

+.025 mm / -.000 mm

Length L

57.2 mm

Clearance Diameter C MAX

41.71 mm

Fastening Hardware

Cap Screw


Screw Material

Alloy Steel with Nypatch®

Hex Wrench Size

5.0 mm

Screw Finish

Black Oxide

Seating Torque

16 Nm

Number of Screws

2 ea

Performance Specifications

Static Torque

9.49 Nm

Angular Misalignment

Dynamic Torque Non-Reversing

4.75 Nm

Parallel Misalignment

0.76 mm

Dynamic Torque Reversing

2.37 Nm

Axial Motion

0.38 mm

Torsional Stiffness

0.28 Deg/Nm

Moment of Inertia

83.407 x10-6 kg-m2

Maximum Speed

6,000 RPM

Additional Information

Material Specification

Type 303 Austenitic, Non-Magnetic Bar


-40°F to 350°F
-40°C to 176°C

Finish Specification



Ruland Manufacturing

Country of Origin


Weight (lbs.)




Product Notes

Note 1

Torque ratings are at maximum misalignment.

Note 2

Performance ratings are for guidance only. The user must determine suitability for a particular application.

Note 3

Torque ratings for the couplings are based on the physical limitations/failure point of the machined beams. Under normal/typical conditions the hubs are capable of holding up to the rated torque of the machined beams. In some cases, especially when the smallest standard bores are used or where shafts are undersized, slippage on the shaft is possible below the rated torque of the machined beams. Please consult technical support for more assistance.

Prop 65

WARNING This product can expose you to chemicals including Ethylene Thiourea and Nickel (metallic), known to the State of California to cause cancer, and Ethylene Thiourea known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

ISO 9001:2015


Conflict Minerals






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