This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X1245S, 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 SI40X1245S
The AirTAC Airtac SI40 Standard Cylinder SI40X1245S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 1245mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X1245S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke1245 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X1245S
- 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 SI40X1245S
The AirTAC SI40X1245S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 1245mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. Because 1245mm exceeds the 1200mm standard maximum for this bore, it is a non-standard, made-to-order length. AirTAC replaced the SI line with the SAI family; the SAI40X1245S is the direct replacement, sharing the same interface, force, and mounting.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. It also adds variants the SI lacked, like the SAIL lock, SAIF valve, and BSAI clamp-lock. The -S suffix means it has a piston magnet for legacy CS1-B/DS1-B sensors; the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X1245S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X1245S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X1245S |
| Bore size | Ø40 mm |
| Stroke | 1245 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 SAI40X1245S 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 SAI40X1245S 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 SI40X1245S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×1245 | 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 SI40X1245S Is Used
Automated Fixture Actuation
Cycles clamps on large assembly jigs, relying on the G1/4 port and ISO 15552 mounts for seamless fixture integration.
Replacing the Airtac SI40 Standard Cylinder SI40X1245S with the SAI40X1245S
To replace the SI40X1245S, order the SAI40X1245S. Confirm the ISO 15552 mounting interface, 40mm bore, 1245mm non-standard stroke, G1/4 port, and your mounting accessory. Because this is a long stroke exceeding 1200mm, you must use external guides to prevent rod bending and side-load damage. If sizing down, a 32mm bore yields 402N at 0.5MPa; sizing up to 50mm yields 982N. A plain cylinder drifts without live air, so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI variant. The SAI family also offers the SAIF integrated valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X1245S
- ✓ 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 SI40X1245S FAQ
Yes, the SI40X1245S is discontinued. The direct replacement is the SAI40X1245S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 1245mm stroke, G1/4 port, and mounting interface.
This double-acting cylinder features a G1/4 air port, M12x1.25 rod thread, and 27mm cushions. 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 SAI40X1245S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X1245S replacement — usually within 7-8 hours.