The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X300-40S is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 40 mm range without swapping the cylinder. Ø250mm bore, 300mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X300-40S is a heavy-duty double-acting single-rod cylinder from the AirTAC SCJ adjustable-stroke series, delivering a powerful 24544 N of push force at 0.5 MPa. Its rear-cap adjusting screw provides up to 40 mm of field-adjustable stroke-end reduction, allowing engineers to fine-tune the stopping position of a 250 mm bore actuator without dismounting the cylinder or adding external hard stops. The built-in magnet (suffix -S) allows direct mounting of CMSG/DMSG/EMSG sensors for reliable end-of-stroke detection.
This ISO 6430 class tie-rod cylinder uses a 50 mm diameter piston rod with an M42x2 knuckle thread and a PT1 inch port, making it suitable for high-thrust forming, pressing, and clamping applications. At the maximum operating pressure of 0.9 MPa, the push force reaches 44178 N, while the pull force is 23562 N at 0.5 MPa due to the single-rod area differential. The 40 mm cushion length and 409 mm body length A(SCJ) ensure robust deceleration and a compact footprint for its force class.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X300-40S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 300 mm |
| Stroke adjustment | Up to 40 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. |
| -40 | 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 bottom-dead-centre position of a large forming press during die setup. The 40 mm adjustment range allows operators to compensate for tooling wear or material thickness variations without mechanical shimming.
Adjust the clamp gap on a structural welding fixture. The SCJ250X300-40S provides 24544 N of clamping force at standard line pressure, and the stroke end can be precisely set to avoid part deformation while ensuring full contact.
Use as an adjustable end-stop on a heavy conveyor system for pallets or large castings. The rear screw allows rapid changeover between product sizes, and the built-in magnet confirms the cylinder has fully retracted to the set position.
Select the SCJ250X300-40S when you need a high-force actuator with the ability to dial in the stroke end position during commissioning or format changes. If your application requires less force, stepping down to a 200 mm bore SCJ reduces the push force to 15708 N at 0.5 MPa. For applications needing a fixed, non-adjustable stroke, the standard SC series offers a simpler, more cost-effective solution.
Because this model has a 300 mm stroke, consider the potential for side loading and rod bending. Use an external guide rail or switch to a guided cylinder if the load is not perfectly axial. For direct replacement, match the 250 mm bore, 300 mm nominal stroke, 40 mm adjust range, PT thread, and the -S magnet option. This model uses the basic mounting style; foot (LB) or centre trunnion (TC) mounts are available as accessories if needed for your machine frame.
Adjustable-stroke checklist
The push force is 24544 N at 0.5 MPa and 44178 N at the maximum operating pressure of 0.9 MPa. The pull force is 23562 N at 0.5 MPa, which is lower due to the area occupied by the 50 mm piston rod on the retract side.
Yes, provided the bore, port thread, and mounting match. The SCJ body length A(SCJ) is 409 mm, which is slightly longer than a fixed-stroke SC of the same bore to accommodate the adjusting screw. Ensure your machine has clearance for the rear adjustment mechanism and confirm the 40 mm adjustment range covers your stroke reduction needs.
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