Description
TS7-25 Setscrew Rigid Coupling – 25 mm OD Mid-Range Aluminum Alloy Precision Coupler
The TS7-25 setscrew type rigid coupling occupies the mid-range position in the TS7 aluminum alloy series, combining a 25 mm outer diameter body with a 1 N·m nominal torque rating and 14,000 rpm maximum speed. This model is the most frequently specified coupling in the TS7 family for standard servo motor to encoder or gearhead output shaft connections, where bore sizes of 8, 10, 11, and 12 mm cover the widest range of commercial servo motor shaft diameters. The step up from M3 to M4 setscrew threading at this frame size increases the available clamping torque — specified wrench torque is 1.7 N·m — improving reliability in sustained-torque or reversing-duty applications where the smaller frame setscrews might require more frequent re-tightening.
The rotational inertia of the TS7-25 is 2.6 × 10⁻⁶ kg·m², calculated at maximum shaft bore. While higher than the smaller frames, this figure remains well within the acceptable range for servo inertia ratio calculations in most standard motion axis designs. At 39 g, the coupling adds negligible mass to the drive train in typical servo-driven axis configurations.
The TS7-25 is manufactured entirely in-house with bore tolerances matched to standard servo motor shaft h6 tolerances. For food processing, pharmaceutical, or corrosion-exposed installations, the dimensionally identical STS7-25 in 316 stainless steel (100 g) is available. Both are listed in detail on our product catalog.
Technical Specifications
| Parameter | Value |
|---|---|
| Model | TS7-25 |
| Body Material | Aluminum Alloy |
| Outer Diameter (D) | 25 mm |
| Overall Length (L) | 36 mm |
| Hub Length (L1) | 9 mm |
| Available Bore Sizes | 8, 10, 11, 12 mm |
| Setscrew Thread | M4 |
| Wrench Torque | 1.7 N·m |
| Rated Torque | 1 N·m |
| Maximum Torque | 2 N·m |
| Maximum Rotational Speed | 14,000 rpm |
| Moment of Inertia | 2.6 × 10⁻⁶ kg·m² |
| Mass | 39 g |
Dimension Drawing
Material and Build Detail
The TS7-25 is machined from high-strength aluminum alloy bar stock. The increase to M4 setscrew threading at this frame size delivers a meaningful improvement in clamping reliability over M3 fasteners, allowing the coupling to sustain rated torque under continuous reversing duty without setscrew loosening. The 9 mm hub length per side provides adequate shaft engagement length for the 1 N·m torque level, balancing compactness against clamping effectiveness.
Typical Applications
- AC and DC servo motor to gearhead output shaft coupling — the 10–12 mm bore range matches the most common servo gearhead output diameters in this torque class
- Rotary encoder to shaft mounting — where the encoder’s 8 mm or 10 mm shaft requires a zero-backlash connection to the measured shaft
- Compact CNC axis drives — particularly Y-axis and A-axis connections on small VMC and turning centres
- Textile machinery position feedback drives — spindle and yarn feed encoder connections
- Semiconductor wafer handling axes — where cleanliness of the aluminum body suits cleanroom environments
Customer Reviews and Case Studies
★★★★★
Taiwan — CNC Machine Tool OEM
We specify the TS7-25 for encoder feedback connections on our servo-driven grinding machine axes. The zero-backlash requirement is absolute in our application — any play introduces position error that shows up directly as surface finish deviation on the workpiece. We have been using this model for three years without a single coupling-related service call.
— Senior Applications Engineer, Taichung
★★★★★
Netherlands — Semiconductor Equipment Integrator
Specified for wafer handling stage drives in a cleanroom environment. The aluminum alloy body was preferred over steel for its outgassing profile and compatibility with cleanroom cleaning protocols. Dimensional accuracy was verified on arrival against our incoming QC template — all units passed without exception.
— Procurement Engineer, Eindhoven
★★★★☆
India — Textile Machinery Manufacturer
Used in spindle encoder coupling on our yarn winding machines. The TS7-25 handles the continuous-duty rotational loading without any performance degradation. We appreciate the mixed bore availability — our motor output is 10 mm and encoder shaft is 8 mm, which the TS7-25 accommodates directly.
— Mechanical Design Manager, Coimbatore
Frequently Asked Questions
Are setscrews included with the TS7-25?
Yes. M4 setscrews are supplied pre-fitted in the coupling body. A hex key of the appropriate size should be used for installation, tightening to 1.7 N·m. Spare setscrews are available on request for maintenance stock.
Can the TS7-25 connect two shafts of different diameters?
Yes. Any combination of the available bore sizes — 8, 10, 11, 12 mm — can be specified independently for d1 and d2. This allows direct connection between, for example, an 8 mm encoder shaft and a 12 mm motor output shaft without any adapter or intermediate component.
What is the difference between TS7-25 and STS7-25?
The TS7-25 is made from aluminum alloy (39 g). The STS7-25 is dimensionally identical but made from 316 stainless steel (100 g). Both carry the same rated torque of 1 N·m and maximum speed of 14,000 rpm. Choose the stainless variant for food processing, pharmaceutical, washdown, or marine environments.
Is thread locking compound recommended for high-vibration applications?
In high-vibration or continuous reversing-torque applications, applying a low-strength thread locking compound to the M4 setscrews before installation is recommended. This prevents self-loosening without significantly increasing disassembly difficulty. A torque wrench should still be used to achieve the specified 1.7 N·m tightening value even with compound applied.
What shaft tolerance is recommended for the TS7-25?
Shaft tolerances of h6 or h7 are recommended. Tighter tolerances improve the fit within the bore and ensure the setscrew clamping force is more uniformly distributed. Loose shaft tolerances (h8 and above) reduce the contact area between shaft and bore, lowering effective torque holding capacity and increasing the risk of shaft movement under load reversals.
Source the TS7-25 From the Manufacturer
Ever Power supplies the TS7-25 and the complete TS7 setscrew rigid coupling series direct from our factory. Submit your bore requirements, quantity, and application details for a prompt technical review and pricing response.
