Two-row recirculating ball bearing linear guide unit RSX series

20 mm5 mm12 mm

Product overview
The RSX series is a miniature full-ball LM guide designed for compact linear motion applications. The series features two rows of raceways in the block and stainless steel construction suitable for corrosive environments.

Key tags

• High accuracy
• 4-way equal load
• 4-way type
• Miniature

Sizes
Available sizes: 5, 7, 9, 12, 15, 20, 25

Types / Model variations

• RSX-SM: Basic dynamic load rating 0.95–9.02 kN; static 1.16–10.6 kN; sizes: 7, 9, 12, 15, 20, 25
• RSX-WSM: Basic dynamic 1.06–5.59 kN; static 1.35–6.78 kN; sizes: 7, 9, 12, 15
• RSX-M: Basic dynamic 0.37–13.3 kN; static 0.53–18.6 kN; sizes: 5, 7, 9, 12, 15, 20, 25
• RSX-WM: Basic dynamic 0.5–7.43 kN; static 0.82–10.1 kN; sizes: 5, 7, 9, 12, 15
• RSX-NM: Basic dynamic 0.45–16.5 kN; static 0.7–25.2 kN; sizes: 5, 7, 9, 12, 15, 20, 25
• RSX-WNM: Basic dynamic 0.64–9.87 kN; static 1.17–15.2 kN; sizes: 5, 7, 9, 12, 15

Structure and features
Balls circulate in two rows of precision-ground raceways in the LM rail and LM block. End plates integrated in the block permit ball recirculation. The two-row contact provides compact outer dimensions while supporting loads in all directions, enabling single-axis installations where moments are present.

Highlighted features
Super compact
One raceway per side on the rail reduces cross-sectional height for installation in constrained spaces.

Corrosion prevention
LM rail, LM block and balls are stainless steel for enhanced corrosion resistance in corrosive environments.

Ball retention
A ball-retaining wire prevents balls from falling out when the block is removed or mounted, simplifying assembly.

Flatness of the LM rail and block mounting surface (examples)
Unit: mm
RSX5 | 0.015 / 200
RSX7 | 0.025 / 200
RSX9 | 0.035 / 200
RSX12 | 0.050 / 200
RSX15 | 0.060 / 200
RSX20 | 0.070 / 200
RSX25 | 0.070 / 200

Notes on mounting surface
Because mounting precision depends on multiple factors, using 70% or less of the above flatness values is recommended. For two or more rails with C1 clearance, use 50% or less.

Reference tightening (bolt torques) for LM block mounting
Unit: N·m (screw depth in mm shown)
RSX5 | M2 | 1.5 mm | 0.4 N·m
RSX7 | M2 | 2.3 mm | 0.4 N·m

Caution
Exceeding the specified torque may affect accuracy. Tighten at or below the listed torque.

Standard lengths and maximum lengths (summary)
Typical LM rail standard lengths and maximum lengths vary by model and accuracy grade. Examples:
RSX5: standard L_O 40, 55, 70, 100, 130, 160; pitch F 15; G,g = 5; max length 220 mm
RSX5W: standard L_O 50, 70, 90, 110, 130, 150, 170; pitch F 20; G,g = 5; max length 220 mm
RSX7: standard L_O 40, 55, 70, 85, 100, 115, 130; pitch F 15; G,g = 5; max length 480 mm
RSX7W: standard L_O 50, 80, 110, 140, 170, 200, 260, 290; pitch F 30; G,g = 10; max length 480 mm
For larger sizes, standard and maximum lengths increase; when maximum length is exceeded, joined rails are used. For special lengths, use values corresponding to G and g dimensions.

Materials and environment
The LM rail, LM block and balls are stainless steel, providing high corrosion resistance and suitability for corrosive or humid environments.

Additional notes

• The ball-contact structure supports loads in all directions, enabling compact single-axis installations with moments.
• Bottom-tapped (tapped-hole) LM rail types are available for improved contamination protection; availability depends on model and grade.

Technical specifications

• Brand: THK
• Model series: RSX
• Product type: Full-Ball LM Guide (Miniature)
• Model variations: RSX-SM, RSX-WSM, RSX-M, RSX-WM, RSX-NM, RSX-WNM
• Sizes available: 5, 7, 9, 12, 15, 20, 25 (varies by model)
• Recirculation: End plates in LM block allow ball recirculation; two rows of raceways
• Material: Stainless steel (LM rail, LM block, balls)
• Corrosion resistance: High
• Special features: Ball-retaining wire; bottom-tapped LM rail option
• Flatness tolerance examples: RSX5 0.015/200 mm — RSX25 0.070/200 mm
• Reference tightening torques examples: RSX5/RSX7: 0.4 N·m (M2 screws)