This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X125H, 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 SI40X125H
The AirTAC Airtac SI40 Standard Cylinder SI40X125H 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 SAI40X125H, 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 → SAI40X125H
- 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 SI40X125H
The AirTAC SI40X125H is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 125mm stroke. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI40X125H. This direct successor shares the exact interface, bore, stroke, force, port and mounting. This specific SKU lacks a magnet (-S) and therefore cannot accept a position switch.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The H designation indicates a Viton H seal, extending operating temperature to 0-150 C. The SAI family also adds SAIL, SAIF and BSAI variants absent from the SI line.
Airtac SI40 Standard Cylinder SI40X125H Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X125H |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X125H |
| 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 SAI40X125H 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 SAI40X125H 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 SI40X125H
| 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 SI40X125H Is Used
Hot End Ejection
Clamping and ejecting small parts near furnaces, utilizing the Viton H seal to withstand ambient temperatures up to 150 C without degrading.
Small Part Pressing
Applying precise 628 N insertion force for seating bearings or pins into housings on automated assembly fixtures.
Replacing the Airtac SI40 Standard Cylinder SI40X125H with the SAI40X125H
To replace the SI40X125H, order the SAI40X125H. Verify the ISO 15552 mounting-interface dimensions, the 125mm stroke, G1/4 port (PT/G/NPT thread options), and your specific mounting accessory (LB, FA, TC, etc.). Because this SKU has no -S magnet, it cannot support legacy CS1-B/DS1-B sensors; order an -S version if sensing is needed. For sizing alternatives, a 32mm bore yields 402 N push at 0.5 MPa, while a 50mm bore yields 982 N. A plain cylinder does not hold load without live air; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. At 125mm stroke, rod bending is low, but ensure guide alignment to prevent side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X125H
- ✓ 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 SI40X125H FAQ
Yes, the AirTAC SI40X125H is discontinued. The direct replacement is the SAI40X125H. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 125mm stroke, 628 N force, G1/4 port, and mounting interface, so it fits existing fixtures directly.
The 40mm bore uses a G1/4 air port. Force ratings are: 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 of 128 kgf at 1.0 MPa. The piston rod is 16mm with an M12x1.25 thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X125H
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X125H replacement — usually within 7-8 hours.