Linear guide with recirculating ball carriage SRS series

caged ball15 mm20 mm

Product overview
Caged Ball LM Guide Model SRS: With a low cross-sectional height LM rail, the SRS delivers a compact, lightweight linear guide. Ball cages eliminate ball-to-ball friction, enabling high speed, low noise, low running sound, long service life and long-term maintenance-free operation.

Key tags

• Long-term maintenance free
• High accuracy
• 4-way equal load
• Miniature

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

Structure and features
The SRS integrates two raceways in a compact block, allowing load support in all directions and use as a single axis where moments occur. Ball cages remove friction between balls and retain lubricant, reducing dust generation. LM block and rail are available in stainless steel for M variants. Partial resin injection molding around ball relief holes reduces block mass and inertia for lightweight, high-speed performance.

Highlighted features

• Low dust generation: cages reduce ball friction and retain lubricant; M variants offer stainless steel block and rail for corrosion resistance.
• Compact: low rail cross-sectional height and single-row ball layout enable installation in limited spaces.
• Lightweight: resin-formed portions reduce mass and inertia for improved dynamic response.

Types / Models (summary of basic load rating ranges and available sizes)

• Model SRS-S — Basic dynamic load rating: 1.09 to 4.50 kN; Basic static load rating: 0.964 to 4.24 kN; Sizes: 7, 9, 12, 15.
• Model SRS-WS — Basic dynamic load rating: 1.38 to 6.64 kN; Basic static load rating: 1.35 to 6.78 kN; Sizes: 7, 9, 12, 15.
• Model SRS-M — Basic dynamic load rating: 0.439 to 16.5 kN; Basic static load rating: 0.468 to 22.3 kN; Sizes: 5, 7, 9, 12, 15, 20, 25.
• Model SRS-WM — Basic dynamic load rating: 0.584 to 9.12 kN; Basic static load rating: 0.703 to 8.59 kN; Sizes: 5, 7, 9, 12, 15.
• Model SRS-N — Basic dynamic load rating: 0.515 to 9.71 kN; Basic static load rating: 0.586 to 11.9 kN; Sizes: 5, 7, 9, 12, 15.
• Model SRS-WN — Basic dynamic load rating: 0.746 to 12.4 kN; Basic static load rating: 0.996 to 15.3 kN; Sizes: 5, 7, 9, 12, 15.

Flatness of the LM Rail and the LM Block Mounting Surface (flatness error table, unit: mm)
Model No. — Flatness error
SRS 5 — 0.015/200
SRS 7 — 0.025/200
SRS 9 — 0.035/200
SRS 12 — 0.050/200
SRS 15 — 0.060/200
SRS 20 — 0.070/200
SRS 25 — 0.070/200

Notes: Many factors affect mounting precision; use values 70% or less of those shown. For two or more rails with C1 clearance, use 50% or less of the shown values.

Standard lengths and maximum lengths (table summary)
Standard rail lengths vary by model and pitch. Examples of standard lengths:
SRS 5 series: 40, 55, 70, 100, 130, 160
SRS 5W series: 50, 70, 90, 110, 130, 150, 170
SRS 7 series: 40, 55, 70, 85, 100, 115, 130
SRS 7W series: 50, 80, 110, 140, 170, 200, 260, 290
Larger series (9 / 12 / 15 / 20 / 25) offer progressively larger standard lengths up to several hundred mm.
Maximum rail length examples (depend on accuracy grade): SRS 5 / 5W: up to 220 mm; SRS 7 / 7W: up to 480 mm; SRS 9 series and larger: up to 2000 mm or more depending on model and grade.

Tapped-hole LM rail type
Bottom-tapped LM rails are available for certain SRS models for base mounting or improved contamination protection. Tap sizes (e.g., M2.6 / M3 / M4 / M5 / M6) vary by model and are available for Precision grade or lower.

Important notes

• "M" in model numbers indicates LM block, LM rail and balls are stainless steel for corrosion resistance.
• SRS-G variants are uncaged full-complement types.
• For SRS5M and SRS5N, balls may fall out of the block if removed from the rail; handle with care.
• Do not use greasing holes for purposes other than greasing to avoid damage.
• Reference tightening torques when mounting LM blocks: SRS 5 — M2 screws, screw depth 1.5 mm, reference torque 0.4 N·m; SRS 7 — M2 screws, screw depth 2.3 mm, reference torque 0.4 N·m. W variants use M3 screws with model-specific torque and depth.

Specifications

• Brand: THK
• Series / Model: SRS
• Product type: Caged Ball LM Guide (Miniature)
• Sizes available: 5, 7, 9, 12, 15, 20, 25
• Model variants: SRS-S, SRS-WS, SRS-M, SRS-WM, SRS-N, SRS-WN (and G / M suffix variants)
• Basic dynamic and static load ratings: model-dependent (see model-specific values)
• Flatness error tolerances: model-dependent (examples: SRS5: 0.015/200 mm; SRS25: 0.070/200 mm)
• Standard and maximum rail lengths: model- and grade-dependent (max values up to ~2000 mm or more)
• Materials: standard steel; M variants: stainless steel for block, rail and balls
• Features: ball cages, low dust generation, compact low-profile rail, resin-formed block portions for weight reduction
• Accessories/options: seals, LaCS/QZ lubricator, tapped-hole rails, grease nipples (not installed when QZ fitted)