$146.34 ea
Quantity Price (USD)
1 $146.34 ea
20 $87.80 ea
60 $73.17 ea
100 $65.85 ea
250 Request Quote
Built to Order Lead Time: 0-2 Days
Ruland MWC20-1/4"-4MM-SS, 1/4" x 4mm Four Beam Coupling, Aluminum, Clamp Style, 0.787" (20.0mm) OD, 1.102" (28.0mm) Length


Ruland MWC20-1/4"-4MM-SS is a four beam coupling with 1/4" x 4mm bores, 0.787" (20.0mm) OD, and 1.102" (28.0mm) length. It is machined from a single piece of material and feature two sets of two spiral cuts. This gives it higher torque capacity, lower windup, and larger body sizes than single beam couplings. MWC20-1/4"-4MM-SS is well suited for applications such as encoders that require high positioning accuracy. MW-series couplings have purely metric outer diameter and length dimensions and fit in a smaller envelope than the P-series allowing for easier interchanges from single beam couplings. This four beam spiral coupling is zero-backlash and has a balanced design for reduced vibration at high speeds of up to 6,000 RPM. All hardware is metric and tests beyond DIN 912 12.9 standards for maximum torque capabilities. MWC20-1/4"-4MM-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. MWC20-1/4"-4MM-SS is manufactured in our Marlborough, MA factory under strict controls using proprietary processes.



Large Bore B1

0.250 in

Small Bore B2

4 mm

B1 Shaft Penetration

0.535 in, 13.6 mm

B2 Shaft Penetration

0.535 in, 13.6 mm

Outer Diameter OD

0.787 in, 20.0 mm

Bore Tolerance

+.001 in / -.000 in, +.025 mm / -.000 mm

Length L

1.102 in / 28.0 mm

Fastening Hardware

Cap Screw


Screw Material

Alloy Steel

Hex Wrench Size

2.5 mm

Screw Finish

Black Oxide

Seating Torque

2.1 Nm

Number of Screws

2 ea

Performance Specifications

Static Torque

1.70 Nm

Angular Misalignment

Dynamic Torque Non-Reversing

1.00 Nm

Parallel Misalignment

0.20 mm

Dynamic Torque Reversing

0.50 Nm

Axial Motion

0.13 mm

Torsional Stiffness

1.29 Deg/Nm

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.

ISO 9001:2015


Conflict Minerals






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