This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125X640, 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 SI125X640
The AirTAC SI125 Standard Cylinder SI125X640 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 640mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125X640, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke640 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125X640
- 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 SI125X640
The AirTAC SI125X640 is a discontinued double-acting ISO 15552 profile cylinder with a 125 mm bore and 640 mm stroke, delivering 6136 N push force at 0.5 MPa via a G1/2 port. As an end-of-life product, it is superseded by the SAI125X640 direct replacement, which matches the original bore, stroke, output force, and ISO 15552 mounting interface.
The SAI upgrade features a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note that this specific SKU lacks a magnet (-S) and therefore cannot accept position sensors.
Airtac SI125 Standard Cylinder SI125X640 Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125X640 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125X640 |
| Bore size | Ø125 mm |
| Stroke | 640 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 SAI125X640 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 SAI125X640 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 SI125X640
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×640 | 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 SI125X640 Is Used
Heavy Press Forming
Drives large press fixtures requiring substantial thrust, utilizing the 6136 N push force at 0.5 MPa to form or stamp metal components reliably.
Pallet Diversion
Actuates heavy-duty diverter arms on conveyor lines, where the 640 mm stroke provides the extended reach needed to redirect wide pallet loads.
Material Lift Gates
Raises and lowers loading dock gates, taking advantage of the 313 kg vertical lift capacity to manage heavy industrial barriers safely.
Replacing the Airtac SI125 Standard Cylinder SI125X640 with the SAI125X640
To replace the SI125X640, order the SAI125X640 and verify your ISO 15552 mounting interface, G1/2 port thread (PT/G/NPT), and accessory type (LB, FA, TC, etc.). Because this 640 mm stroke exceeds 300 mm, use an external guide to prevent rod bending and premature seal wear from side loads. Sizing alternatives include stepping down to an 80 mm bore (2513 N push @0.5 MPa) for lighter loads or up to a 160 mm bore (10053 N push @0.5 MPa) for heavier demands. The air cushion only decelerates the piston at stroke ends; it will not hold a load on air loss. For static holding, specify the SAIL or BSAI lock variant, or use an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125X640
- ✓ 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 SI125X640 FAQ
Yes, the SI125X640 is discontinued. The direct replacement is the SAI125X640. It is dimensionally interchangeable per ISO 15552, matching the 125 mm bore, 640 mm stroke, output force, G1/2 port, and mounting accessories.
This double-acting cylinder features a G1/2 air port and a 32 mm piston rod. It 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125X640
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125X640 replacement — usually within 7-8 hours.