Airtac JSI Series Standard Cylinder JSI125X300S
The AirTAC Airtac JSI Series Standard Cylinder JSI125X300S is a genuine double acting JIS-standard air cylinder with a Ø125mm bore and 300mm 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
- Stroke300 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 JSI125X300S
Delivering 6136 N of push force at 0.5 MPa, this double-acting JIS-standard profile cylinder is built for heavy-duty automation. Because it uses an extruded hard-anodized aluminum barrel instead of external rods, the JSI125X300S is noticeably shorter and more compact than an ISO 15552 cylinder of the same 125 mm bore, saving valuable machine space. The integrated -S piston magnet allows CMSE or DMSE switches to drop directly into the side grooves for precise position detection.
The heterogeneous two-way piston seal retains grease for a long, low-friction service life, while the 33 mm adjustable air cushions at both ends absorb impact near the stroke limits. Plan for about 3682 N of real work at 0.5 MPa, which means it can safely lift a 313 kg vertical load with a 2:1 safety margin. It features a G1/2 air port, an M27x2.0 rod-end thread, and operates at speeds between 30 and 500 mm/s.
Airtac JSI Series Standard Cylinder JSI125X300S Technical Specifications
| Model | Airtac JSI Series Standard Cylinder JSI125X300S |
|---|---|
| Series | JSI JIS-standard profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 300 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 JSI125X300S
| JSI | JIS-standard profile cylinder (double-acting type). |
|---|---|
| 125 | Bore size in mm (32 / 40 / 50 / 63 / 80 / 100 / 125). |
| ×300 | 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 JSI125X300S Is Used
Stamping Press Feeder
Pushes heavy coil stock into a mechanical stamping press, utilizing the 6136 N push force to overcome material friction and guide resistance.
Pallet Dispenser
Indexes empty wooden pallets into an automated packaging line, where the 300 mm stroke provides the exact travel needed to load a stacker.
Injection Mold Ejector
Acts as a heavy-duty knockout for large plastic injection molds, using the 33 mm adjustable cushions to decelerate the massive 125 mm bore piston smoothly.
Is the Airtac JSI Series Standard Cylinder JSI125X300S the Right Cylinder?
If 6136 N of push at 0.5 MPa is more than your process requires, stepping down to the JSI100X300S offers 3927 N and a lighter G1/2 footprint. There is no larger bore in the JSI series, so for loads exceeding this 125 mm unit's capacity, you would need to gang two cylinders or switch to a different system. Because this SKU includes the -S magnet, it is fully ready for CMSE and DMSE sensors.
With a 300 mm stroke, the 32 mm piston rod is subjected to higher bending moments under off-center loads. To prevent premature seal wear and rod deformation, always use an external guide rail to support the load and avoid side-loading the cylinder. Remember that the air cushions only decelerate the piston near the end caps; they do not act as a brake. If the machine loses air pressure, the piston will drift, so install an external rod lock or a pilot-operated check valve to hold a suspended load safely in place.
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 JSI125X300S FAQ
At 0.5 MPa, this 125 mm bore cylinder provides 6136 N of push force and 5734 N of pull force. At 0.7 MPa, it delivers 8590 N push and 8028 N pull. The theoretical maximum force is 1251 kgf at 1.0 MPa. It uses a G1/2 air port and features an M27x2.0 rod-end thread.
The JSI125X300S is a JIS-standard profile cylinder that is shorter and more compact than an ISO 15552 cylinder of the same 125 mm bore. It achieves this space saving through an extruded hard-anodized aluminum barrel design that eliminates external tie rods while maintaining structural integrity.
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