Airtac JSI Series Standard Cylinder JSI125X285
The AirTAC Airtac JSI Series Standard Cylinder JSI125X285 is a genuine double acting JIS-standard air cylinder with a Ø125mm bore and 285mm stroke, G1/2 air ports and adjustable end cushioning. Its no-tie-rod, hard-anodized profile barrel is more compact than an ISO 15552 cylinder of the same bore — a space-saver on tight machines.
- BoreØ125 mm
- Stroke285 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- CushionAdjustable, 33 mm
- 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 JSI Series Standard Cylinder JSI125X285
Delivering massive thrust in a tight footprint, the AirTAC JSI125X285 is a JIS-standard double-acting profile cylinder that is physically shorter and more compact than an equivalent ISO 15552 unit of the same bore. The extruded hard-anodized aluminum barrel completely eliminates external rods, resisting wear while keeping the assembly light. At 0.5 MPa it pushes with 6136 N and pulls with 5734 N, peaking at a theoretical 1251 kgf at 1.0 MPa.
For real-world sizing, plan for about 3682 N of actual work at 0.5 MPa, which safely lifts around 313 kg vertically with a 2:1 margin. The internal two-way piston seal retains grease for a long, low-friction service life, and the G1/2 ports feed the 32 mm rod at speeds of 30-500 mm/s. Because this specific SKU lacks the -S magnet, it cannot accept CMSE or DMSE position switches without upgrading to the sensed variant.
Airtac JSI Series Standard Cylinder JSI125X285 Technical Specifications
| Model | Airtac JSI Series Standard Cylinder JSI125X285 |
|---|---|
| Series | JSI JIS-standard profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 285 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 33 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC JSI (JIS standard) datasheet. Confirm against the product label before installation. Thread options: PT (blank) / G. Barrel: hard-anodized aluminum profile (no tie rods).
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac JSI Series Standard Cylinder JSI125X285
| JSI | JIS-standard profile cylinder (double-acting type). |
|---|---|
| 125 | Bore size in mm (32 / 40 / 50 / 63 / 80 / 100 / 125). |
| ×285 | Stroke length in mm. |
| -S | Optional built-in magnet for CMSE / DMSE sensors. |
JSI-family variants: JSI (double acting), JSID (double rod), JSIJ (adjustable stroke). Mounting: LB / FA / FB / CA / CB / CR / TC / TCM1 / TCM2. Thread PT (blank) / G.
Where the Airtac JSI Series Standard Cylinder JSI125X285 Is Used
Heavy Press Ejection
Provides the rugged 6136 N push force needed to eject dense steel stampings from a hydraulic press bed without occupying excessive machine footprint.
Pallet Stopper Gate
Acts as a high-force stop gate in automated pallet conveyors, reliably halting 300 kg loads using the adjustable 33 mm air cushions to absorb impact.
Injection Mold Clamping
Secures heavy injection molding tooling halves, leveraging the 125 mm bore thrust to maintain rigid alignment during the clamping phase.
Is the Airtac JSI Series Standard Cylinder JSI125X285 the Right Cylinder?
As the largest bore in the JSI range, there is no larger standard size to step up to if 6136 N at 0.5 MPa proves insufficient; you would instead need to parallel two cylinders or change the system pressure. Stepping down, the 100 mm bore provides 3927 N push at 0.5 MPa, offering a lighter alternative if your load permits. For the 285 mm stroke, ensure external guide rails are used to prevent rod bending under heavy lateral loads. Since air loss or a centered valve will cause the piston to drift, an external rod lock or pilot-operated check valve is required to suspend any vertical load safely.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT / G / NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Side load — consider a guided cylinder
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Avoid side load on the piston rod.
- check Set cushions to minimum, then release gradually.
- check Use correct mounting accessory (LB/FA/FB/CA/CB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac JSI Series Standard Cylinder JSI125X285 FAQ
This 125 mm bore cylinder uses a G1/2 air port and a 32 mm rod with an M27x2.0 thread. It generates 6136 N push and 5734 N pull at 0.5 MPa, or 8590 N push and 8028 N pull at 0.7 MPa, with a theoretical maximum of 1251 kgf at 1.0 MPa. Operating speed ranges from 30-500 mm/s.
It is a JIS-standard profile cylinder that is shorter and more compact than an ISO 15552 cylinder of the same 125 mm bore. Because this specific SKU does not include the -S magnet, it cannot support CMSE or DMSE magnetic switches; you must select the -S variant for sensor groove integration.
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