This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX125S, 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 SI50AX125S
The AirTAC SI50 Standard Cylinder SI50AX125S 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 SAI50AX125S, 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 → SAI50AX125S
- 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 SI50AX125S
The AirTAC SI50AX125S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 125mm stroke. Featuring a stainless SUS420J2 piston rod and a built-in magnet for CS1-B/DS1-B sensors, it delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this EOL unit with the SAI50AX125S.
The SAI50AX125S is a direct replacement, matching the ISO 15552 mounting interface, bore, output force, and cushioning. It upgrades the piston seal to two Y-shaped one-way elements for low start-up pressure. For load holding, note that cushions only decelerate; use a SAIL or BSAI lock variant.
Airtac SI50 Standard Cylinder SI50AX125S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX125S |
| 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 SAI50AX125S 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 SAI50AX125S 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 SI50AX125S
| 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 SI50AX125S Is Used
Mid-Tonnage Clamping
Secures workpieces in CNC machining fixtures using the 982N push force, with the SUS420J2 stainless rod resisting coolant corrosion.
Package Diverting
Actuates routing gates on packaging lines, where the 125mm stroke provides sufficient travel to redirect products efficiently.
Replacing the Airtac SI50 Standard Cylinder SI50AX125S with the SAI50AX125S
To replace the SI50AX125S, order the SAI50AX125S. It drops into existing fixtures via the identical ISO 15552 mounting interface, matching the 50mm bore, 125mm stroke, G1/4 port, and M16x1.5 rod thread. Confirm your mounting accessory (LB, FA, TC, etc.) and the -S magnet requirement for current AirTAC switches. Sizing both ways: this 50mm bore yields 982N push at 0.5MPa, whereas the neighboring 40mm bore provides 628N. If you need to hold position without live air, the cushion only decelerates; select the SAIL lock or BSAI clamp-lock variant, or add an external pilot check valve. The SAIF variant integrates a 4M valve if space is tight.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX125S
- ✓ 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 SI50AX125S FAQ
Yes, the AirTAC SI50AX125S is discontinued. The direct replacement is the SAI50AX125S. It features the same ISO 15552 mounting interface, 50mm bore, 125mm stroke, G1/4 port, and output force, fitting existing fixtures perfectly while upgrading the piston seal.
This double-acting cylinder has a G1/4 port. It generates 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical maximum of 200kgf at 1.0MPa. The rod is 20mm with an M16x1.5 thread, and speed ranges 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX125S replacement — usually within 7-8 hours.