This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X778S, 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 SI50 Standard Cylinder SI50X778S
The AirTAC Airtac SI50 Standard Cylinder SI50X778S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 778mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X778S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke778 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X778S
- 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 SI50 Standard Cylinder SI50X778S
The AirTAC SI50X778S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 778mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50X778S, matching the exact ISO 15552 mounting interface, stroke, force and porting for existing fixtures.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. It adds SAIL lock, SAIF valve and BSAI clamp variants the SI lacked. The -S magnet works with CS1-B/DS1-B sensors, and Viton H seals raise heat to 150C.
Airtac SI50 Standard Cylinder SI50X778S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X778S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X778S |
| Bore size | Ø50 mm |
| Stroke | 778 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50X778S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50X778S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50X778S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×778 | 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 SI50 Standard Cylinder SI50X778S Is Used
Pneumatic Press Eject
Ejects formed parts using 1374N force at 0.7MPa, benefiting from the SAI's upgraded Y-shaped seals for low start-up pressure.
Replacing the Airtac SI50 Standard Cylinder SI50X778S with the SAI50X778S
To replace the SI50X778S, order the SAI50X778S. Confirm the ISO 15552 interface, 50mm bore, 778mm stroke, G1/4 port (PT/G/NPT) and mounting accessory. The -S magnet enables CS1-B/DS1-B sensors, though the SAI uses current AirTAC switches. For sizing, a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore yields 1559N. At 778mm, prevent rod bending by using external guides to manage side loads. The air cushion only decelerates; it does not hold load on air loss. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X778S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50X778S FAQ
Yes, the SI50X778S is discontinued. The direct replacement is the SAI50X778S. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 778mm stroke, G1/4 port, force and mounting interface.
It features a G1/4 port and M16x1.5 rod thread. Force output is 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical max of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X778S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X778S replacement — usually within 7-8 hours.