This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X70STC, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI125 Standard Cylinder SI125X70STC
The AirTAC SI125 Standard Cylinder SI125X70STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 70mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X70STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke70 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X70STC
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI125 Standard Cylinder SI125X70STC
The AirTAC SI125X70STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 70 mm stroke. It delivers 6136 N push force at 0.5 MPa through a G1/2 port. AirTAC replaced this legacy unit with the SAI125X70STC, a direct replacement sharing the exact ISO 15552 mounting interface, bore, stroke, force, port and TC trunnion mount.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL and BSAI lock variants the SI line lacked.
Airtac SI125 Standard Cylinder SI125X70STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X70STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X70STC |
| Bore size | Ø125 mm |
| Stroke | 70 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125X70STC carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125X70STC produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125X70STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×70 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI125 Standard Cylinder SI125X70STC Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136 N push force to maintain rigid clamping under high vibration.
Automated Assembly Lifts
Raises and lowers heavy subassembly platforms using the TC trunnion mount to accommodate side-load pivoting during the lift cycle.
Replacing the Airtac SI125 Standard Cylinder SI125X70STC with the SAI125X70STC
To replace the SI125X70STC, order the SAI125X70STC. Confirm the ISO 15552 TC trunnion mounting interface, the 125 mm bore, the 70 mm stroke, the G1/2 port, and the -S magnet for CS1-B/DS1-B sensors. If you need more force, the neighboring 160 mm bore offers 10053 N push at 0.5 MPa; if less force is acceptable, the 100 mm bore provides 3927 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The 32 mm rod and M27x2 thread remain unchanged.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X70STC
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125X70STC FAQ
Yes, the SI125X70STC is discontinued. The direct replacement is the SAI125X70STC. It is dimensionally interchangeable per ISO 15552, retaining the same bore, stroke, force, G1/2 port, and TC mounting interface.
This 125 mm bore cylinder features a G1/2 port. It generates 6136 N push and 5734 N pull at 0.5 MPa, 8590 N push at 0.7 MPa, 11045 N push at 0.9 MPa, and a theoretical maximum force of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X70STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X70STC replacement — usually within 7-8 hours.