This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X300STC, 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 SI50X300STC
The AirTAC SI50 Standard Cylinder SI50X300STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 300mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X300STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke300 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X300STC
- 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 SI50X300STC
The AirTAC SI50X300STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 300mm stroke. It delivers 982N push and 825N pull at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X300STC, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, output force and TC trunnion accessory.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. The SAI family also adds SAIL, SAIF and BSAI lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors, while SAI uses current AirTAC switches.
Airtac SI50 Standard Cylinder SI50X300STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X300STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X300STC |
| Bore size | Ø50 mm |
| Stroke | 300 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 SAI50X300STC 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 SAI50X300STC 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 SI50X300STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×300 | 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 SI50X300STC Is Used
Material Diverting
Drives a 300mm diverting arm on a packaging line, using the TC trunnion to pivot packages smoothly between parallel conveyor belts.
Vertical Lift Gate
Raises and lowers a 50kg access gate.
Component Ejection
Pushes machined parts out of a CNC enclosure. The adjustable 30mm air cushions absorb kinetic energy at stroke ends, while the -S magnet tracks position.
Replacing the Airtac SI50 Standard Cylinder SI50X300STC with the SAI50X300STC
To replace the SI50X300STC, order the SAI50X300STC. Confirm the ISO 15552 TC trunnion mount, 50mm bore, 300mm stroke, G1/4 port (PT/G/NPT thread options) and the -S magnet. Sizing both ways: a 63mm bore yields 1559N push at 0.5MPa, while a 40mm bore yields 628N. If you need to hold the load on air loss, note that a plain SAI drifts and its cushion only decelerates; use an external pilot check valve, rod lock, or the SAIL/BSAI lock variant. Because the 300mm stroke is long, use an external guide to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X300STC
- ✓ 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 SI50X300STC FAQ
Yes, the SI50X300STC is discontinued. The direct replacement is the SAI50X300STC. It shares the identical ISO 15552 mounting interface, 50mm bore, 300mm stroke, output force, G1/4 port and TC trunnion mount, fitting directly into existing fixtures.
The 50mm bore uses a G1/4 air port and an 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 maximum of 200kgf at 1.0MPa. It operates at 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X300STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X300STC replacement — usually within 7-8 hours.