This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X125STC, 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 SI50X125STC
The AirTAC Airtac SI50 Standard Cylinder SI50X125STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X125STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X125STC
- 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 SI50X125STC
The AirTAC SI50X125STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 125mm stroke, and TC trunnion mounting. Delivering 982 N push force at 0.5 MPa, it is directly replaced by the SAI50X125STC. This direct upgrade shares the exact same ISO 15552 mounting interface, G1/4 port, and output force. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life.
The original SI utilized CS1-B/DS1-B sensors via its -S magnet, while the SAI family uses current AirTAC switches. The SAI line also introduces variants the SI lacked, such as the SAIL air-released lock, SAIF integrated valve, and BSAI clamp-lock. Rod material options include carbon steel, SUS420J2 (A), or SUS304 (B).
Airtac SI50 Standard Cylinder SI50X125STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X125STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X125STC |
| Bore size | Ø50 mm |
| Stroke | 125 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 SAI50X125STC 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 SAI50X125STC 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 SI50X125STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | 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 SI50 Standard Cylinder SI50X125STC Is Used
Conveyor Diverter
Pushes packages at a 90-degree angle using 982 N of force, with TC trunnion mounting handling the offset pivotal stresses during transit.
Clamp Actuation
Secures medium-density workholding fixtures, relying on the 125mm stroke to clear the part entirely before robotic loading.
Replacing the Airtac SI50 Standard Cylinder SI50X125STC with the SAI50X125STC
To replace the discontinued SI50X125STC, order the SAI50X125STC. Verify your existing fixture accepts the ISO 15552 TC trunnion mount, 50mm bore, 125mm stroke, and G1/4 port. The -S magnet allows for position sensing; ensure you use current AirTAC switches for the SAI (legacy CS1-B/DS1-B switches belong to the SI). When sizing, the 50mm bore yields 982 N push at 0.5 MPa; if undersized, the neighboring 63mm bore provides 1559 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding, specify the SAIL lock variant, BSAI clamp-lock, or an external pilot check valve. Stroke is under 300mm, so rod-bending side loads are minimal, but standard guide rules still apply.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X125STC
- ✓ 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 SI50X125STC FAQ
Yes, the SI50X125STC is discontinued. The direct replacement is the SAI50X125STC. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 125mm stroke, G1/4 port, TC mount, and output force.
The 50mm bore features a G1/4 air port and an M16x1.5 rod thread. Force output is 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X125STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X125STC replacement — usually within 7-8 hours.