The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X300-50 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, 300mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X300-50 is a double-acting, single-rod pneumatic cylinder from AirTAC's adjustable-stroke SCJ series, built on a rugged tie-rod platform. With a 250 mm bore and a nominal 300 mm stroke, it delivers a substantial 24544 N of push force at 0.5 MPa, making it suitable for heavy pressing, clamping, and forming operations. The rear-cap adjusting screw provides a 50 mm field-adjustable range to fine-tune the stroke end position without removing the cylinder from the machine.
This ISO 6430 class cylinder features a 50 mm diameter piston rod with an M42x2 thread and a PT 1-inch port. It includes an adjustable air cushion (40 mm length) for smooth deceleration of high-inertia loads. The body length A is 409 mm, and the maximum standard stroke for this bore is 1500 mm. Operating pressure ranges from 0.15 to 1.0 MPa, with a proof pressure of 1.5 MPa.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X300-50 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 300 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. |
| ×300 | 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.
A hydraulic-style press using pneumatics for a fast approach and retract can use the 50 mm adjustment screw to precisely set the final pressing depth for different part batches, ensuring consistent results without complex tooling changes.
For modulating large industrial valves, the adjustable stroke allows field engineers to fine-tune the open/closed positions of the valve gate or ball, accommodating wear and ensuring a perfect seal over thousands of cycles.
In a steel plate bending or forming fixture, the SCJ250 can be adjusted to control the final bend angle. The 50 mm screw range lets operators compensate for material spring-back without reprogramming the entire pneumatic sequence.
Select the SCJ250X300-50 when you need a high-force actuator with the ability to dial in the stroke end precisely during commissioning or changeovers. If your force requirement is slightly lower, consider stepping down to the 200 mm bore, which provides 15708 N of push force at 0.5 MPa. For applications needing a fixed, non-adjustable stroke, the standard SC series is a simpler alternative. This cylinder is a direct replacement for an existing AirTAC SCJ250X300-50 with a 50 mm adjust range, PT port thread, and basic mounting.
Given the 300 mm stroke length, be mindful of potential side-loading on the 50 mm rod. For applications with significant lateral forces, an external guide rail or a switch to a guided cylinder is recommended to prevent rod bending and ensure long seal life.
Adjustable-stroke checklist
At the standard operating pressure of 0.5 MPa, this cylinder generates 24544 N of push force and 23562 N of pull force. At the maximum operating pressure of 1.0 MPa, the theoretical push force reaches 5006 kgf (approx. 49088 N). The push force is higher than the pull force due to the area of the single 50 mm piston rod.
A rear-cap adjusting screw allows you to shorten the stroke end by up to 50 mm. This is for fine-tuning the end position, not for changing the nominal 300 mm stroke rating. It can replace an SC cylinder of the same bore and stroke if you need this field-adjustability, but the SCJ body is slightly longer to house the mechanism. Ensure the mounting and port thread (PT 1 inch) match your current setup.
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