This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX850S, 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 SI40BX850S
The AirTAC Airtac SI40 Standard Cylinder SI40BX850S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 850mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX850S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke850 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX850S
- 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 SI40BX850S
The AirTAC SI40BX850S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 850mm stroke, and a SUS304 stainless piston rod. Generating 628N push force at 0.5MPa, it is replaced by the SAI40BX850S. This direct successor shares the exact interface, port, and force, but adds an upgraded piston seal with two Y-shaped elements for lower start-up pressure and longer life.
The G1/4 port and M12x1.25 rod thread remain unchanged. The original -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family introduces SAIL, SAIF, and BSAI lock variants. Note that plain cylinders drift without air; use a pilot check valve for holding.
Airtac SI40 Standard Cylinder SI40BX850S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX850S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX850S |
| Bore size | Ø40 mm |
| Stroke | 850 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 SAI40BX850S 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 SAI40BX850S 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 SI40BX850S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×850 | 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 SI40BX850S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the 850mm stroke, with the SUS304 rod resisting moisture in washdown areas.
Vertical Lift Gate
Raises lightweight access gates; the 32kg vertical lift capacity at 0.5MPa handles standard panel weights safely.
Corrosive Material Handling
Actuates tooling in chemical processing where the SUS304 stainless rod prevents rust and degradation over long extensions.
Replacing the Airtac SI40 Standard Cylinder SI40BX850S with the SAI40BX850S
To replace the SI40BX850S, order the SAI40BX850S, confirming the ISO 15552 mounting interface, 40mm bore, 850mm stroke, G1/4 port, and SUS304 rod. The SAI drops directly into existing fixtures. If sizing down, a 32mm bore yields 402N push at 0.5MPa; sizing up to 50mm provides 982N. For load holding, a plain cylinder drifts when air is lost—its cushions only decelerate. Use an external rod lock or pilot check valve, or specify the SAIL or BSAI lock variant. At 850mm, prevent rod bending by guiding the load externally to avoid side-loading.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX850S
- ✓ 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 SI40BX850S FAQ
Yes, the SI40BX850S is discontinued. The direct replacement is the SAI40BX850S. It shares the same ISO 15552 mounting interface, 40mm bore, 850mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
The 40mm bore features a G1/4 port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX850S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX850S replacement — usually within 7-8 hours.