This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X420, 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 SI50X420
The AirTAC Airtac SI50 Standard Cylinder SI50X420 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 420mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X420, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke420 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X420
- 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 SI50X420
The AirTAC SI50X420 is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 420 mm stroke, delivering 982 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X420, a direct sharing the exact interface, bore, stroke, force, port and mounting.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. Note this non-magnet SKU cannot take a sensor. For high heat, Viton H seals raise temps to 150 C.
Airtac SI50 Standard Cylinder SI50X420 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X420 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X420 |
| Bore size | Ø50 mm |
| Stroke | 420 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 SAI50X420 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 SAI50X420 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 SI50X420
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×420 | 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 SI50X420 Is Used
Long-Stroke Diversion
Pushes packages across transfer lines with 982 N push at 0.5 MPa, utilizing the 420 mm stroke to clear adjacent conveyor lanes.
Pallet Positioning
Shifts lightweight pallets into staging zones, safely operating within the 589 N working load limit and 50 kg vertical lift margin.
Material Lowering
Lowers workpieces over 420 mm; external guides must support the rod against side-load, while end cushions decelerate the mass.
Replacing the Airtac SI50 Standard Cylinder SI50X420 with the SAI50X420
To replace the SI50X420, order the SAI50X420 confirming the ISO 15552 mounting interface, 50 mm bore, 420 mm stroke, G1/4 port and mounting accessory. This non-S SKU lacks a magnet and cannot accept CS1-B/DS1-B sensors. Sizing both ways: a 63 mm bore gives 1559 N push at 0.5 MPa, while a 40 mm bore yields 628 N. At 0.7 MPa this 50 mm bore pushes 1374 N. A plain cylinder drifts on air loss; for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The 420 mm stroke requires external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X420
- ✓ 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 SI50X420 FAQ
Yes, the AirTAC SI50X420 is discontinued. The direct replacement is the SAI50X420, which shares the identical ISO 15552 mounting interface, 50 mm bore, 420 mm stroke, output force, G1/4 port and accessories.
The bore features a G1/4 port. 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 max of 200 kgf at 1.0 MPa.
Request a Quote for the SAI50X420
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X420 replacement — usually within 7-8 hours.