The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-40 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, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-40 is a heavy-duty double-acting, single-rod pneumatic cylinder with a rear adjusting screw that provides up to 40 mm of field-adjustable stroke-end control. With a 250 mm bore and 50 mm diameter piston rod, it delivers a substantial 24544 N of push force at 0.5 MPa, making it suitable for large-scale clamping, pressing, and positioning tasks where the final stroke length must be fine-tuned during commissioning or after tooling wear.
This ISO 6430 class tie-rod cylinder features a 1-inch PT port and an M42x2 rod thread, with a generous 40 mm air cushion at each end for reliable deceleration. The body length A for this SCJ configuration is 409 mm, providing a robust platform for heavy industrial applications. The 40 mm adjustment range allows operators to shorten the stroke end without dismounting the cylinder, a critical advantage for maintaining precise end positions on large machinery.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-40 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 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. |
| ×400 | 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.
Adjust the final pressing depth on large hydraulic-style pneumatic presses during die setup or after tooling changes, ensuring consistent part dimensions without reprogramming the entire stroke.
Fine-tune the closed position of heavy industrial dampers or material flow gates to compensate for seal wear or build-up, maintaining a tight shut-off over thousands of cycles.
Set a precise, repeatable deflection limit on large-scale structural test fixtures, where the 40 mm adjustment screw allows quick reconfiguration for different test specimens.
Select the SCJ250X400-40 when you need the highest force output in the SCJ range and the ability to dial in the stroke end position on the machine. If the 24544 N push force at 0.5 MPa is more than required, stepping down to the 200 mm bore provides 15708 N of push force in a lighter package. For applications where the stroke length is fixed and will never need field adjustment, the standard SC250X400 fixed-stroke cylinder is a simpler, more cost-effective alternative. At a 400 mm stroke, always assess the rod for potential side-loading; an external guide rail or a switch to a guided cylinder is recommended if the load is not perfectly axial to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
At the standard 0.5 MPa operating pressure, the push force is 24544 N and the pull force is 23562 N. The force increases linearly with pressure, reaching a maximum push force of 44178 N at the 0.9 MPa maximum operating pressure.
You can replace a fixed-stroke cylinder with the SCJ250X400-40 if you need the 40 mm stroke-end adjustment feature. Ensure the replacement matches the 250 mm bore, PT port thread, and your required mounting style. The SCJ mounting pattern is a subset of the SC series, so verify your existing brackets are compatible with the basic, FA, LB, or TC/TCM1 options.
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