SCS40 Aluminum Shaft Collar – 40 mm Bore, M8 Screw, OD 70 mm, 12 mm Keyway, 18 mm Wide
The SCS40 shaft collar marks a decisive move into heavy industrial territory with the introduction of an M8 clamping screw — the first in the SCS series above M6. An M8 socket-head cap screw at rated torque delivers roughly twice the clamping force of an M6. Combined with the 70 mm OD and 18 mm face width, the SCS40 achieves clamping performance that rivals many solid-bore ring designs at this shaft size.
The 12 mm keyway (DIN 6885A 12×8, available to order) is the standard used on output shafts of industrial gearboxes in the 1.5 kW to 7.5 kW range, on heavy machine tool spindles, and on drive shafts of steel processing and metalworking equipment.
Technical Specifications – SCS40
| Parameter | Value | Notes |
|---|---|---|
| Model | SCS40 | Single-split clamp type |
| Bore (d) | 40 mm | Fits Ø40 shafts |
| Outer Diameter (D) | 70 mm | Wall thickness 15.0 mm per side |
| Width (B) | 18 mm | Axial face width |
| Clamping Screw | M8 | Countersunk socket-head cap screw |
| Slit Width (W) | 2 mm | Opening gap for shaft insertion |
| Keyway (K) | 12 | Standard; custom keyway on request |
| Material | Aluminium alloy | ~2.7 g/cm³, corrosion resistant |
Design Features and Performance Advantages
⚡ M8 Screw: Twice the Force of M6
Industrial-grade clamping — M8 at rated torque delivers force levels that rival solid-ring designs at this shaft size.
🏗 Machine Tool Grade Precision
18mm wide face, precision-ground face option available — suitable for angular contact bearing preload datum applications.
⚙ 12mm Keyway: Gearbox-Standard Key
DIN 6885A 12×8 key fits the output shafts of 1.5kW–7.5kW industrial gearboxes — no shaft modification required.
📈 70mm OD, 15mm Wall Per Side
Heavy wall section maintains bore closure geometry even with 12mm keyway slot — robust clamping at full key depth.
Application Sectors
▶ Machine Tool Lead-Screw and Ball-Screw Fixed-End Positioning
40 mm is a common journal diameter for ball-screws used in X and Y axes of vertical machining centres in the mid-range power class. The SCS40 at the fixed bearing end defines the axial datum for the angular contact bearing pair, maintaining the screw's positional stiffness across the machine's entire service life.
▶ Steel Processing Line Drive Shafts
Slitting and levelling lines for steel coil processing use 40 mm shafts on main drive roller journals. The SCS40 with 12 mm keyway secures the drive gear or sprocket against the very high torque and axial thrust generated by steel-coil processing speeds, where collar slippage would cause immediate mis-register and scrap product.
▶ Heavy Agricultural and Construction Equipment PTO Shafts
Power take-off drive lines in heavy farm machinery and construction equipment use 40 mm internal shafts for mid-drive speed changes. The SCS40's M8 grip force and 12 mm keyway capacity handles the high shock torques and torsional reversal impulses that characterise off-road agricultural PTO duty cycles.
Installation and Mounting Notes
The 18 mm face width provides a 50% longer bore contact than the 12 mm face of mid-range models, substantially reducing shaft surface stress and increasing resistance to rocking — the tendency of a collar to tilt slightly on the shaft axis under eccentric axial loads. Rocking is a particular concern in cantilevered load situations where the collar must resist both an axial force and a bending moment. For machine tool applications, precision-ground face SCS40 collars are available — contact EP for machine tool accuracy-grade options.
Frequently Asked Questions – SCS40
What tightening torque is recommended for the M8 screw in the SCS40?
For M8 socket-head cap screws in aluminium: 18–22 N·m. Always use a calibrated torque wrench. For high-vibration or shock-load applications, apply medium-strength thread-locking compound and re-inspect torque after the first 50 operating hours.
How does the 12mm keyway compare to the 10mm keyway of the SCS35 in terms of torque capacity?
The DIN 6885A 12×8 key has a shear area approximately 40% larger than the 10×8 key for a given engagement length on a 40mm vs 35mm shaft. The combination of larger shaft diameter and wider key makes the SCS40 keyway connection substantially stronger in torque.
Can the SCS40 be dynamically balanced for high-speed spindle applications?
Yes. Dynamic balancing to ISO 1940 balance grades (G2.5, G1.0) is available as a factory option. Specify the rotational speed and required balance grade when ordering.
Is the SCS40 available in stainless steel for corrosive environments?
The SCS series is offered in aluminium alloy as standard. For stainless steel shaft collars at 40mm bore, contact EP — a separate stainless steel collar range is available with comparable dimensions.
Order SCS40 for Machine Tool and Heavy Drive Applications
MOQ 100 pcs | M8 industrial screw | Precision-ground face on request