This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX25, 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 SI50BX25
The AirTAC Airtac SI50 Standard Cylinder SI50BX25 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX25, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX25
- 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 SI50BX25
The AirTAC SI50BX25 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 25mm stroke, delivering 982 N push force at 0.5 MPa. The direct replacement is the SAI50BX25, matching the interface, port, and force. This specific SKU lacks a magnet, so it cannot accept position sensors.
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 absent from the SI line.
Airtac SI50 Standard Cylinder SI50BX25 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX25 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX25 |
| Bore size | Ø50 mm |
| Stroke | 25 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 SAI50BX25 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 SAI50BX25 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 SI50BX25
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×25 | 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 SI50BX25 Is Used
Short-Stroke Clamping
Ideal for holding workpieces in machining fixtures where a 982 N push force securely locks parts for milling or drilling operations.
Carton Flap Folding
Provides the precise 25mm travel and 825 N pull force needed to fold small corrugated box flaps smoothly at high cycling speeds.
Inline Product Diverting
Mounts directly to conveyor frames using ISO 15552 accessories to push lightweight goods off the belt into secondary packaging lanes.
Replacing the Airtac SI50 Standard Cylinder SI50BX25 with the SAI50BX25
To replace the SI50BX25, order the SAI50BX25. Verify the ISO 15552 mounting interface, 50mm bore, 25mm stroke, G1/4 port, and M16x1.5 rod thread. Because this SKU has no magnet (-S), it cannot support legacy CS1-B/DS1-B sensors; order a magnet-equipped SAI if sensing is needed. For sizing, a 40mm bore yields 628 N [email protected], while a 63mm bore yields 1559 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX25
- ✓ 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 SI50BX25 FAQ
Yes, the AirTAC SI50BX25 is discontinued. The direct replacement is the SAI50BX25, a true ISO 15552 profile cylinder with the same 50mm bore, 25mm stroke, G1/4 port, and mounting dimensions. It fits existing fixtures perfectly.
It features a G1/4 air port. The force ratings are: 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa. It operates at speeds of 30-800 mm/s.
Request a Quote for the SAI50BX25
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX25 replacement — usually within 7-8 hours.