SCS20 Aluminum Shaft Collar – 20 mm Bore, OD 40 mm, Lightweight Gearbox Shaft Positioning
The SCS20 shaft collar is built for the 20 mm shaft diameter — the single most prevalent output shaft size across the global catalogue of worm gear reducers, helical gearboxes, and fractional-horsepower direct-drive motors. From small Chinese gearmotors to US-made NEMA-frame drives, 20 mm is the de facto standard output shaft for drives in the 100 W to 1.5 kW power band that dominates light-to-medium industrial automation.
The SCS20 shares the 40 mm OD and 12 mm face width with the SCS18. Its aluminium construction means it weighs approximately one-third of a steel collar with identical dimensions — a meaningful advantage on rotating shafts where minimising added inertia supports servo system tuning.
Technical Specifications – SCS20
| Parameter | Value | Notes |
|---|---|---|
| Model | SCS20 | Single-split clamp type |
| Bore (d) | 20 mm | Fits Ø20 shafts |
| Outer Diameter (D) | 40 mm | Wall thickness 10.0 mm per side |
| Width (B) | 12 mm | Axial face width |
| Clamping Screw | M5 | Countersunk socket-head cap screw |
| Slit Width (W) | 1.5 mm | Opening gap for shaft insertion |
| Keyway (K) | 6 | Standard; custom keyway on request |
| Material | Aluminium alloy | ~2.7 g/cm³, corrosion resistant |
Design Features and Performance Advantages
🌐 Universal 20mm Gearbox Standard
20mm shaft is the global output standard for 100W–1.5kW drives — SCS20 is the direct-fit collar for the world's most common gearbox output.
⚖ 1/3 Weight of Steel Equivalent
Aluminium construction cuts rotating inertia vs steel — supports tighter servo loop tuning and faster dynamic response.
⚙ Reposition Without Shaft Rework
Hex-key adjustment replaces machined shoulders — essential for machines with frequent product changeovers.
📈 6mm Keyway for Drive Hubs
DIN 6885A 6×6 key-compatible keyway available to retain sprockets and pulleys rotationally as well as axially.
Application Sectors
▶ Worm Gear Reducer Output Shaft Collars
20 mm is the catalogue output shaft size for the most widely sold worm gear reducer frame sizes worldwide. SCS20 collars at the reducer output bearing face prevent the output shaft from floating axially under the thrust component of worm gear mesh forces, protecting the bearing from fretting wear.
▶ Conveyor Head Pulley Shaft Retention
Head pulley shafts in light-to-medium duty belt conveyors — food processing, pharmaceutical packaging, e-commerce sorting — run at 20 mm in many compact conveyor frame designs. The SCS20's corrosion-resistant aluminium construction suits food-adjacent environments where steel collar rust staining is a hygiene concern.
▶ Material Handling Hoist and Winch Drums
Compact electric hoist and winch assemblies use 20 mm drum shafts. An SCS20 provides axial retention preventing the drum from walking along the shaft under cyclic rope tension load, maintaining consistent rope-wrap alignment across the drum face.
Installation and Mounting Notes
The SCS20 is frequently used in pairs to provide bilateral axial retention for gear hubs, sprockets, and coupling halves on 20 mm gearbox shafts. Unlike a machined shaft shoulder, the SCS20 pair can be repositioned with nothing more than a hex key — preferred in machinery that undergoes regular product changeovers. For applications where the SCS20 must survive high-speed rotation (above 4,000 rpm), EP can supply dynamically balanced collars — specify rotational speed and balance grade (ISO 1940 G-grade) when ordering via the contacts page.
Frequently Asked Questions – SCS20
How does the SCS20 compare to a steel shaft collar of the same size?
The aluminium SCS20 is approximately one-third the weight of an equivalent steel collar. It offers comparable clamping force via the M5 screw at rated torque, but a lower maximum operating temperature (120 °C vs 200 °C for carbon steel) and lower resistance to heavy abrasive environments.
Can the SCS20 be used on a stainless steel gearbox shaft?
Yes. In marine or food-processing environments where galvanic corrosion between aluminium and stainless steel could be a concern, apply a thin film of neutral grease or use an anodised collar to provide barrier protection at the interface.
What keyway size is standard for 20mm shaft drives?
For a 20 mm shaft, DIN 6885A specifies a 6×6 parallel key. The SCS20 keyway option is machined to this standard. If your application uses a 5 mm key, specify this in your order drawing.
Is the SCS20 available in a solid (non-split) configuration?
The SCS series is exclusively single-split clamp type. Solid shaft collars are available in EP's separate catalogue range — contact the team for that product family.
Replace Steel Collars with Lightweight SCS20
MOQ 100 pcs | Steel-to-aluminium upgrade | Custom keyway on request