This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X310STC, 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 SI125X310STC
The AirTAC SI125 Standard Cylinder SI125X310STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 310mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X310STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke310 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X310STC
- 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 SI125X310STC
The AirTAC SI125X310STC is a discontinued double-acting ISO 15552 profile cylinder delivering 6136 N push and 5734 N pull at 0.5 MPa. AirTAC replaced this legacy unit with the SAI125X310STC, a direct replacement retaining the exact 125 mm bore, 310 mm stroke, G1/2 port, TC trunnion mount and ISO 15552 mounting interface. The SAI upgrade features a revised piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. It also introduces SAIL, SAIF and BSAI lock variants absent from the original SI line.
The rod material options include carbon steel, SUS420J2 or SUS304, and seal choices span TPU, NBR and Viton H for up to 150 C. The built-in magnet supports legacy CS1-B/DS1-B sensors, while the SAI family uses current AirTAC switches.
Airtac SI125 Standard Cylinder SI125X310STC Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X310STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X310STC |
| Bore size | Ø125 mm |
| Stroke | 310 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 SAI125X310STC 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 SAI125X310STC 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 SI125X310STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×310 | 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 SI125X310STC Is Used
Heavy Press Clamping
Secures large metal castings during machining operations, utilizing the 6136 N push force at 0.5 MPa to hold components firmly against fixture stops.
Pallet Lift Stations
Raises loaded pallets in distribution hubs, matching the 313 kg vertical lift capacity to elevate goods smoothly between conveyor tiers.
Bulk Material Diversion
Actuates heavy-duty diverter arms on aggregate lines, using the TC trunnion mount to handle rotational stress during high-speed package routing.
Replacing the Airtac SI125 Standard Cylinder SI125X310STC with the SAI125X310STC
To replace the SI125X310STC, order the SAI125X310STC. Verify the ISO 15552 TC trunnion interface, 125 mm bore, 310 mm stroke, G1/2 port (PT/G/NPT) and the -S magnet for sensing. 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 higher force, the 160 mm bore provides 14074 N at 0.7 MPa. Note that a plain cylinder drifts on air loss because the cushion only decelerates; for load holding, specify the SAIL or BSAI lock variant, or use an external rod lock. Because the 310 mm stroke is long, prevent rod bending by guiding the load externally to avoid side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X310STC
- ✓ 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 SI125X310STC FAQ
Yes, the SI125X310STC is discontinued. The direct replacement is the SAI125X310STC. It matches the ISO 15552 mounting interface, 125 mm bore, 310 mm stroke, output force, G1/2 port and TC trunnion, fitting existing fixtures directly.
The G1/2 port bore delivers 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 maximum theoretical force of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X310STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X310STC replacement — usually within 7-8 hours.