The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-50 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, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-50 is a double-acting, single-rod pneumatic cylinder from the AirTAC SCJ adjustable-stroke series, offering a 250 mm bore and a nominal 400 mm stroke. Its defining feature is a rear-cap adjusting screw that provides a 50 mm field-adjustable range, allowing engineers to fine-tune the stroke end position without removing the cylinder from the machine. This model delivers a substantial push force of 24544 N at 0.5 MPa, making it suitable for heavy-duty industrial actuation where precise end-stop calibration is required.
Built on a robust tie-rod construction, this ISO 6430 class cylinder uses a 50 mm diameter piston rod with an M42x2 thread and a PT 1 inch port. The unit includes an adjustable air cushion (40 mm long) for controlled deceleration and operates within a standard temperature range of -20 to +70 °C. With a body length A(SCJ) of 409 mm, it is a direct replacement for any AirTAC SCJ250X400-50 of the same configuration, ensuring drop-in compatibility for maintenance and upgrades.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-50 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 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. |
| ×400 | 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.
Fine-tune the pressing depth in large hydraulic-pneumatic forming presses. The 50 mm adjustment range allows operators to compensate for tooling wear or material thickness variations without disassembling the tooling.
Control the opening position of a diverter gate on a heavy-duty conveyor for mining or aggregate. The adjustable stroke lets technicians precisely set the gate angle to manage material flow rates during commissioning.
Use in a fatigue testing machine for large structural components. The rear adjusting screw provides a quick method to set the zero point of the actuator stroke after a test specimen is mounted, ensuring accurate and repeatable test cycles.
Select the SCJ250X400-50 when you need a high-force actuator with the ability to dial in the final stroke end position during commissioning or format changes. If your application requires less force, stepping down to a 200 mm bore SCJ reduces push force to 15708 N at 0.5 MPa, while still offering the same adjustable-stroke convenience. For applications where the stroke is fixed and never needs field adjustment, a standard SC250X400 fixed-stroke cylinder is a more economical choice.
At a 400 mm stroke length, managing side loads is critical to prevent rod bending and premature seal wear. For applications with significant lateral forces, pair this cylinder with an external guide rail system or consider a guided cylinder assembly. When replacing an existing unit, ensure the new cylinder matches the exact bore (250 mm), nominal stroke (400 mm), 50 mm adjust range, PT port thread, and basic mounting configuration.
Adjustable-stroke checklist
The theoretical push force at 0.5 MPa is 24544 N, and the pull force on the retract stroke is 23562 N due to the area of the 50 mm piston rod. At the maximum operating pressure of 1.0 MPa, the theoretical push force reaches 5006 kgf.
The rear-cap adjusting screw limits how far the piston can extend by shortening the stroke end. It is designed for fine-tuning the stroke length within a 50 mm range, not as a high-impact mechanical stop. The screw sets the end position, but the cylinder's internal air cushion should be used to decelerate the load before it contacts the screw.
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