Airtac BSAI Locking Clamp Cylinder BSAI125X25
The AirTAC Airtac BSAI Locking Clamp Cylinder BSAI125X25 is a genuine double-acting ISO 15552 cylinder with a Ø125mm bore, 25mm stroke and a spring-applied, air-released clamp-lock that holds the rod at ANY position along its travel — with a static holding force of 8600 N.
- BoreØ125 mm
- Stroke25 mm
- Cylinder portG1/2
- TypeSingle rod (BSAI)
- Enclasp portG1/8
- Rod threadM27×2
About the Airtac BSAI Locking Clamp Cylinder BSAI125X25
The AirTAC BSAI125X25 is a double-acting ISO 15552 profile cylinder with a spring-applied, air-released enclasp mechanism. It clamps the carbon steel piston rod to hold a static load of 8600 N at any position along its 25 mm travel. The cylinder delivers 6136 N of thrust at 0.5 MPa, but the holding force is a separate mechanical grip capacity, meaning you must size the clamp strength against your load weight, not the pneumatic thrust.
This bidirectional lock engages only after the rod has stopped, serving as a holding brake rather than a dynamic stopper. A third G1/8 enclasp port controls the release, requiring balanced air pressure on both piston sides to prevent the rod from jumping abruptly upon unlocking. The variable air cushion at the stroke ends only decelerates the piston; it does not hold the load.
Airtac BSAI Locking Clamp Cylinder BSAI125X25 Technical Specifications
| Model | Airtac BSAI Locking Clamp Cylinder BSAI125X25 |
|---|---|
| Series | BSAI ISO 15552 clamp-lock cylinder |
| Bore size | Ø125 mm |
| Stroke | 25 mm |
| Type | Single rod (BSAI), double acting |
| Cylinder port | G1/2 |
| Rod thread | M27×2 |
| Lock type | Spring-applied, air-released clamp (any position) |
|---|---|
| Static holding force | 8600 N |
| Enclasp / unlock port | G1/8 |
| Operating pressure | 0.15 – 0.7 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Max stroke | Up to 1000 mm |
Specifications follow the official AirTAC BSAI datasheet (ISO 15552). Operating pressure is 0.15–0.7 MPa (lower than a plain SAI). Port options: PT / G.
How the Clamp-Lock Holds
static holding force (Ø125 mm)
A spring-applied gripper clamps the rod and holds the load at any position in the stroke — not just at the stroke end (that is a SAIL) — and it is bidirectional: it holds whether the rod was extending or retracting.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa (max) | 8590 N | — |
Push/pull as tabulated. Rated to the 0.7 MPa operating maximum for this series. The clamp holding force (8600 N) is separate from cylinder thrust. Size with a margin.
Where the Airtac BSAI Locking Clamp Cylinder BSAI125X25 Is Used
Heavy Vertical Axis Holding
Locks a 8600 N payload securely at any intermediate height on vertical lifts, preventing sudden drops during air pressure loss.
Machining Position Lock
Clamps the rod rigidly during heavy milling or drilling operations, ensuring the workpiece platform remains totally stationary.
Power Failure Safety Hold
The spring-applied enclasp engages automatically upon air loss, freezing the rod exactly where it stopped to protect operators and tooling.
Is the Airtac BSAI Locking Clamp Cylinder BSAI125X25 the Right Clamp-Lock?
Choose this 125 mm bore if your payload exceeds the holding capacity of the 100 mm bore, which offers 5500 N of holding force and 3927 N of thrust at 0.5 MPa. For lighter loads, stepping down reduces air consumption. The BSAI125X25 is preferred over a SAIL stroke-end lock when you must secure the rod mid-travel, whereas a plain SAI cylinder suffices if no holding is needed. This model features PT tapered ports, a robust M27x2 rod thread for high side-load resistance, and accepts Basic, FA, FB, CA, CB, CR, LB, TC, TCM1, and TCM2 mounts. Because no magnet is specified, it will not work with CMSE or DMSE sensors.
Quick checklist
- ✓ Hold needed at any position?
- ✓ Or stroke-end only → use SAIL
- ✓ Holding force ≥ your load
- ✓ Balanced-pressure unlock circuit
- ✓ Extra safety measure for people
Airtac BSAI Locking Clamp Cylinder BSAI125X25 FAQ
The built-in clamp-lock provides a static holding force of 8600 N. It locks the rod bidirectionally at any position along the 25 mm stroke, but only after the rod has completely stopped moving.
The lock is released via a third G1/8 enclasp port. You must balance the air pressure on both sides of the piston before unlocking, otherwise the rod can jump abruptly. It is a holding brake, not a dynamic stopping device.
Related AirTAC Lock & Standard Cylinders
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