This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X250STC, 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 SI50X250STC
The AirTAC SI50 Standard Cylinder SI50X250STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X250STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X250STC
- 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 SI50X250STC
The AirTAC SI50X250STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 250mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50X250STC, matching the interface, bore, stroke, force and TC trunnion mount.
The SAI upgrade features a two Y-shaped one-way piston seal 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.
Airtac SI50 Standard Cylinder SI50X250STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X250STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X250STC |
| Bore size | Ø50 mm |
| Stroke | 250 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 SAI50X250STC 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 SAI50X250STC 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 SI50X250STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×250 | 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 SI50X250STC Is Used
Package Diversion
Drives a 250mm stroke diverter arm on a packaging line, using the 982N push force at 0.5MPa to redirect cartons reliably without overwhelming the TC trunnion mount.
Vertical Lift Gate
Raises a lightweight access gate.
Clamp Actuation
Secures medium workpieces in a machining fixture. The G1/4 port and 30-800mm/s speed range provide rapid, stable clamping, while the -S magnet enables position confirmation.
Replacing the Airtac SI50 Standard Cylinder SI50X250STC with the SAI50X250STC
To replace the SI50X250STC, order the SAI50X250STC. Confirm the ISO 15552 TC trunnion interface, 50mm bore, 250mm stroke, G1/4 port (PT/G/NPT thread) and the -S magnet. At 0.5MPa it yields 982N push and 825N pull; if undersized, the neighbouring 63mm bore gives 1559N. For 250mm strokes, ensure guide alignment to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X250STC
- ✓ 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 SI50X250STC FAQ
Yes, the SI50X250STC is discontinued. The direct replacement is the SAI50X250STC. It is dimensionally interchangeable per ISO 15552, keeping the same 50mm bore, 250mm stroke, TC trunnion mount, G1/4 port and 982N force, so it fits existing fixtures directly.
This double-acting cylinder has a G1/4 air port. The thrust figures are 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X250STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X250STC replacement — usually within 7-8 hours.