The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X125-50S is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 50 mm range without swapping the cylinder. Ø250mm bore, 125mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X125-50 is a double-acting, single-rod pneumatic cylinder from AirTAC, engineered for heavy-duty applications where field-adjustable stroke end position is critical. With a 250 mm bore and a 50 mm rod, it delivers a substantial 24544 N of push force at 0.5 MPa, making it suitable for pressing, clamping, and material handling tasks that demand high force. The rear-cap adjusting screw provides a 50 mm range to fine-tune the piston's end stop, allowing operators to dial in the exact stroke needed without swapping the cylinder or adding external hard stops.
This model features a built-in magnet, enabling direct mounting of CMSG/DMSG/EMSG sensors for reliable, non-contact position sensing along the tie-rod barrel. The standard TPU seals offer a good balance of wear resistance and dynamic performance within a -20 to +70 C temperature range. The body length A for this SCJ series is 409 mm, and the integrated air cushion, with a length of 40 mm, effectively decelerates the high-inertia load at the end of its travel, reducing noise and mechanical shock.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X125-50S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 50 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1" |
| Rod thread | M42×2 |
| 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, 40 mm |
| Max stroke | Up to 1500 mm |
Specifications follow the official AirTAC SCJ (adjustable-stroke) datasheet. The rear adjusting screw sets the stroke end position; force is the same as the equivalent single-rod SC bore. Confirm against the product label before installation. Thread options: PT (standard) / G.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 24544 N | 23562 N |
| 0.7 MPa | 34361 N | — |
| Max (@1.0 MPa) | 5006 kgf | |
SCJ is single-rod, so force matches the equivalent SC bore: push uses the full bore area, pull subtracts the rod area. Actual usable force is lower than theoretical due to friction and back-pressure; size with a safety margin.
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 250 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -50 | Adjustable-stroke range in mm (options 10/20/30/40/50/75/100). |
| -S | Optional built-in magnet for sensor position sensing. |
Related types: SC (single rod, fixed stroke), SCD (double rod), SCT (multi-position). SCJ mounting: Basic, FA, LB, TC, TCM1. Seals: TPU standard / H = Viton / N = NBR. Thread: blank = PT, G = G thread.
During the setup of a large bearing press, the 50 mm adjustable stroke allows operators to precisely dial in the final press depth for different part tolerances without reprogramming the machine, ensuring consistent assembly quality.
Used as an end-of-line pallet stop on a conveyor, the adjustable stroke lets maintenance staff quickly compensate for wear on the contact pad or change the stopping position for a new pallet size, minimizing downtime.
In a large welding fixture, the cylinder clamps a structural beam. The stroke-end adjustment screw is used to set the exact closed position of the clamp arm, preventing over-travel that could distort the workpiece while applying 24544 N of force.
Select the SCJ250X125-50 when you need a high-force actuator with the flexibility to adjust the stroke end position by up to 50 mm during commissioning or format changes. If your application requires even greater force, consider stepping up to a larger bore; if less force is needed, the SCJ200 series provides 15708 N of push force at 0.5 MPa. For applications requiring a fixed, non-adjustable stroke, the standard SC series is a more economical choice. This cylinder is a direct replacement for another AirTAC SCJ250X125-50 with a PT port, basic mounting, and a magnet. For strokes of 300 mm or more, carefully evaluate side-loading on the 50 mm rod; an external guide rail or a guided cylinder assembly is recommended to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
The theoretical push force at 0.5 MPa is 24544 N, and the pull force is 23562 N. At the maximum operating pressure of 1.0 MPa, the push force reaches 44178 N. The pull force is lower because the rod reduces the effective piston area on the return stroke.
A rear-cap adjusting screw limits the piston's forward travel, allowing you to shorten the stroke end by up to 50 mm from its 125 mm nominal maximum. This is a mechanical end-stop adjustment for setting stroke length, not a locking device. The cylinder will not hold its position if air pressure is lost; an external rod lock or pilot-operated check valve is required for load holding.
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