This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X270STC, 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 SI50X270STC
The AirTAC Airtac SI50 Standard Cylinder SI50X270STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 270mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X270STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke270 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X270STC
- 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 SI50X270STC
The AirTAC SI50X270STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 270mm stroke. It delivers a thrust of 982 N at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X270STC, a direct sharing the same ISO 15552 mounting interface, bore, stroke, output force, port and TC trunnion accessory.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also introduces SAIL, SAIF and BSAI lock variants absent in the SI line. Your -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50X270STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X270STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X270STC |
| Bore size | Ø50 mm |
| Stroke | 270 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 SAI50X270STC 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 SAI50X270STC 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 SI50X270STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×270 | 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 SI50X270STC Is Used
Package Diversion
Actuates sorting arms on packaging lines, utilizing the 982 N push force at 0.5 MPa to reliably push 50 kg cartons onto secondary chutes.
Pallet Positioning
Indexes empty pallets within automated storage systems using the TC trunnion mount to accommodate slight misalignment during 270mm travel.
Clamp Actuation
Drives mid-force clamping fixtures on machining cells, where the adjustable 30mm air cushions decelerate the 20mm rod smoothly at stroke end.
Replacing the Airtac SI50 Standard Cylinder SI50X270STC with the SAI50X270STC
To replace the SI50X270STC, order the SAI50X270STC. Confirm the ISO 15552 TC trunnion mounting, 50mm bore, 270mm stroke, G1/4 port (PT/G/NPT thread options) and the -S magnet for CS1-B/DS1-B switches. Sizing both ways: the neighbouring 63mm bore yields 1559 N push at 0.5 MPa, while dropping to 40mm gives 628 N. Because this 270mm stroke exceeds 300mm? No, but at 270mm you should still evaluate side-load and rod-bending forces, using a guide to prevent premature seal wear. A plain cylinder drifts without live air; for load holding use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X270STC
- ✓ 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 SI50X270STC FAQ
Yes, the SI50X270STC is discontinued. The direct replacement is the SAI50X270STC. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 270mm stroke, G1/4 port, TC mounting and output force. You simply order the SAI equivalent for your existing fixtures.
The 50mm bore features a G1/4 air port and a 20mm rod. It generates a push force of 982 N and a pull force of 825 N at 0.5 MPa. At 0.7 MPa push is 1374 N, and at 0.9 MPa it is 1767 N. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X270STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X270STC replacement — usually within 7-8 hours.