This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X50STC, 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 SI125X50STC
The AirTAC SI125 Standard Cylinder SI125X50STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 50mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X50STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke50 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X50STC
- 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 SI125X50STC
The AirTAC SI125X50STC is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore, 50 mm stroke, and TC trunnion mounting. Delivering 6136 N push force at 0.5 MPa through a G1/2 port, it is replaced by the direct replacement SAI125X50STC. The SAI retains the exact ISO 15552 mounting interface, bore, stroke, force, port, and TC mount, fitting existing fixtures perfectly.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors; SAI uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X50STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X50STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X50STC |
| Bore size | Ø125 mm |
| Stroke | 50 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 SAI125X50STC 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 SAI125X50STC 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 SI125X50STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×50 | 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 SI125X50STC Is Used
Heavy Press Clamping
Applies 6136 N of thrust at 0.5 MPa to secure large steel fabrications during machining or welding operations.
Pallet Load Shifting
Uses the short 50 mm stroke and TC trunnion mount to push heavy palletized goods smoothly onto transfer conveyors.
Mold Ejection Systems
Provides robust 125 mm bore push force to eject dense composite or metallic parts from heavy industrial molds.
Replacing the Airtac SI125 Standard Cylinder SI125X50STC with the SAI125X50STC
To replace the SI125X50STC, order the SAI125X50STC. Confirm the ISO 15552 TC trunnion mount, 125 mm bore, 50 mm stroke, G1/2 port (PT/G/NPT thread options), and the -S magnet. Sizing both ways: a 100 mm bore yields 3927 N push at 0.5 MPa, while a 160 mm bore yields 10053 N. If you need to hold a load without live air, note that a plain cylinder drifts (the 40 mm cushion only decelerates); use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The M27x2 rod and 30-500 mm/s speed remain unchanged.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X50STC
- ✓ 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 SI125X50STC FAQ
Yes, the SI125X50STC is discontinued. The direct replacement is the SAI125X50STC. It shares the same ISO 15552 TC mounting interface, 125 mm bore, 50 mm stroke, 6136 N force, and G1/2 port, fitting your existing fixtures perfectly.
This 125 mm bore cylinder features a G1/2 port, M27x2 rod thread, and 40 mm cushions. Force ratings are: push 6136 N and pull 5734 N at 0.5 MPa, push 8590 N at 0.7 MPa, push 11045 N at 0.9 MPa, with a theoretical max of 1251 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X50STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X50STC replacement — usually within 7-8 hours.