This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI63X51S, 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 SI63 Standard Cylinder SI63X51S
The AirTAC Airtac SI63 Standard Cylinder SI63X51S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø63mm bore and 51mm stroke, G3/8 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI63X51S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ63 mm
- Stroke51 mm
- Port sizeG3/8
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI63X51S
- 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 SI63 Standard Cylinder SI63X51S
The AirTAC SI63X51S is a discontinued double-acting ISO 15552 profile cylinder with a 63 mm bore, 51 mm stroke, and a G3/8 air port. Delivering 1559 N push force at 0.5 MPa, it is replaced by the SAI63X51S. This direct upgrade shares the exact ISO 15552 mounting interface, bore, stroke, output force, and porting, fitting existing fixtures perfectly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The original SI line lacked lock variants, but the SAI family adds SAIL, SAIF, and BSAI options. With the -S magnet, this model supports legacy CS1-B/DS1-B sensors.
Airtac SI63 Standard Cylinder SI63X51S Technical Specifications
| Model | Airtac SI63 Standard Cylinder SI63X51S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI63X51S |
| Bore size | Ø63 mm |
| Stroke | 51 mm |
| Acting type | Double acting |
| Port size | G3/8 |
| 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 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI63X51S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø63mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 1559 N | 1402 N |
| 0.7 MPa | 2182 N | — |
| Max (@1.0 MPa) | 318 kgf | |
The SAI63X51S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI63 Standard Cylinder SI63X51S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 63 | Bore size in mm. |
| ×51 | 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 SI63 Standard Cylinder SI63X51S Is Used
Mid-Tonnage Clamping
Secures heavy workpieces in CNC machining fixtures using 1559 N of thrust at 0.5 MPa.
Short-Stroke Diverting
Actuates routing gates on packaging lines where a compact 51 mm shift is required.
Pallet Stopper Arms
Deploys heavy-duty stop mechanisms for 79 kg vertical load handling at conveyor ends.
Replacing the Airtac SI63 Standard Cylinder SI63X51S with the SAI63X51S
To replace the SI63X51S, order the SAI63X51S. Confirm the ISO 15552 mounting interface, 63 mm bore, 51 mm stroke, G3/8 port (PT/G/NPT), and mounting accessory. The -S suffix means a piston magnet is present for CS1-B/DS1-B switches. If you need more force, the 80 mm bore yields 2513 N push at 0.5 MPa; if less is required, the 50 mm bore provides 982 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The 20 mm rod and M16x1.5 thread handle standard loads, but always guide external mechanisms to prevent side-load bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI63X51S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI63 Standard Cylinder SI63X51S FAQ
Yes, the SI63X51S is discontinued. The direct replacement is the AirTAC SAI63X51S. It is dimensionally interchangeable per ISO 15552, matching the 63 mm bore, 51 mm stroke, G3/8 port, and mounting interface.
The G3/8 port bore delivers 1559 N push and 1402 N pull at 0.5 MPa, 2182 N push at 0.7 MPa, 2805 N push at 0.9 MPa, and a theoretical max of 318 kgf at 1.0 MPa. Speed is 30-800 mm/s.
Request a Quote for the SAI63X51S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI63X51S replacement — usually within 7-8 hours.