This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X420S, 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 SI40X420S
The AirTAC Airtac SI40 Standard Cylinder SI40X420S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 420mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X420S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke420 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X420S
- 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 SI40X420S
The AirTAC SI40X420S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 420 mm stroke. It delivers 628 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X420S, a direct sharing the exact interface, bore, stroke, force and mounting.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life, while the SAI family adds SAIL, SAIF and BSAI lock variants. This -S model carries a piston magnet for CS1-B/DS1-B sensors, and seal options include Viton H for high heat.
Airtac SI40 Standard Cylinder SI40X420S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X420S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X420S |
| Bore size | Ø40 mm |
| Stroke | 420 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 SAI40X420S 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 SAI40X420S 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 SI40X420S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×420 | 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 SI40X420S Is Used
Component Ejection
Ejects machined parts from a fixture with adjustable 27 mm air cushions at both ends decelerating the rod before impact.
Replacing the Airtac SI40 Standard Cylinder SI40X420S with the SAI40X420S
To replace the SI40X420S, order the SAI40X420S keeping the identical 40 mm bore, 420 mm stroke, G1/4 port and ISO 15552 mounting. Confirm your thread standard (PT, G or NPT) and mounting accessory (like FA flange or TC trunnion). The -S suffix means a magnet is present for CS1-B/DS1-B switches; the SAI uses current AirTAC switches. Sizing both ways: a 50 mm bore offers 982 N push at 0.5 MPa, while dropping to 32 mm yields 402 N. Because the 420 mm stroke exceeds 300 mm, use an external guide to prevent rod bending and side-load damage. A plain cylinder drifts without air; for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X420S
- ✓ 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 SI40X420S FAQ
Yes, the AirTAC SI40X420S is discontinued. The direct replacement is the SAI40X420S. It shares the identical ISO 15552 mounting interface, 40 mm bore, 420 mm stroke, output force, G1/4 port and accessories, fitting directly into existing fixtures.
The 40 mm bore features a G1/4 air port and M12x1.25 rod thread. Force output is 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. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X420S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X420S replacement — usually within 7-8 hours.