This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X125STC, 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 SI40 Standard Cylinder SI40X125STC
The AirTAC Airtac SI40 Standard Cylinder SI40X125STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X125STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X125STC
- 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 SI40 Standard Cylinder SI40X125STC
The AirTAC SI40X125STC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 125mm stroke. It delivers 628 N push force at 0.5 MPa through a G1/4 port. The direct replacement is the SAI40X125STC, which matches the original TC trunnion mount, M12x1.25 rod thread, and output force exactly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S suffix means a piston magnet for CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X125STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X125STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X125STC |
| Bore size | Ø40 mm |
| Stroke | 125 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X125STC carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X125STC produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X125STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×125 | 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 SI40 Standard Cylinder SI40X125STC Is Used
Package Diversion
Actuates sorting gates on packaging lines, using the 628 N push force to reliably redirect cartons at 30-800 mm/s.
Clamp Actuation
Secures medium-duty workpieces in machining fixtures, providing repeatable 125mm travel via the TC trunnion mount.
Replacing the Airtac SI40 Standard Cylinder SI40X125STC with the SAI40X125STC
To replace the SI40X125STC, order the SAI40X125STC. Verify the ISO 15552 TC trunnion mounting interface, 40mm bore, 125mm stroke, G1/4 port, and the -S magnet. If you need more force, the neighbouring 50mm bore yields 982 N push at 0.5 MPa; if less is acceptable, the 32mm bore provides 402 N. Because this is a double-acting cylinder, it will not hold a load without live air—the cushion only decelerates. For load holding, consider the SAIL lock variant, BSAI clamp-lock, or an external pilot check valve. At 125mm stroke, side-load is minimal, but always ensure proper guide alignment to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X125STC
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X125STC FAQ
Yes, the AirTAC SI40X125STC is discontinued. The direct replacement is the SAI40X125STC. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 125mm stroke, G1/4 port, TC trunnion mount, and output force, so it drops directly into existing fixtures.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical maximum force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X125STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X125STC replacement — usually within 7-8 hours.