The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X250-40 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, 250mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X250-40 is a double-acting, single-rod pneumatic cylinder with a field-adjustable stroke end, built on a robust tie-rod construction conforming to ISO 6430 class dimensions. Its 250 mm bore and 50 mm rod diameter generate substantial force—24544 N pushing and 23562 N pulling at 0.5 MPa—making it suitable for heavy-duty clamping, pressing, and positioning tasks where the final stroke length must be fine-tuned during commissioning or changeover. The rear-cap adjusting screw provides up to 40 mm of stroke-end reduction without dismounting the cylinder.
This model features a 1-inch PT port, an M42x2 rod thread, and a 40 mm air cushion to decelerate the piston smoothly. The body length A(SCJ) is 409 mm, slightly longer than the fixed-stroke SC equivalent to accommodate the adjusting mechanism. Operating pressure spans 0.15–1.0 MPa, with a proof pressure of 1.5 MPa, and the standard TPU seal works reliably from -20 to +70 °C. The adjustable screw sets only the stroke end position; it does not alter force output or speed.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X250-40 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 250 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. |
| ×250 | 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-center position of a large forming or laminating press during initial setup, accommodating tooling tolerances without machining custom spacers.
Adjust the clamping stroke on a welding or assembly jig for large structural frames, allowing operators to compensate for part variation and ensure consistent contact pressure.
Set the precise open or closed position of a large butterfly or gate valve in a process line, using the 40 mm adjustment range to match the valve's mechanical limits exactly.
Choose the SCJ250X250-40 when you need to dial in the exact end-of-stroke position on a large-bore actuator without adding external hard stops. If the 24544 N push force at 0.5 MPa is more than required, stepping down to a 200 mm bore reduces push force to 15708 N. For applications needing a fixed, non-adjustable stroke, the standard SC series offers a simpler, slightly shorter body. This cylinder is a direct replacement for another AirTAC SCJ250 adjustable-stroke unit with a 250 mm nominal stroke, 40 mm adjust range, PT ports, and basic mounting. For strokes of 300 mm or more, evaluate side-loading on the 50 mm rod; an external guide rail or a guided cylinder may be necessary to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
At the standard 0.5 MPa operating pressure, the cylinder delivers 24544 N of push force and 23562 N of pull force. The maximum push force at 0.9 MPa is 44178 N. The rear adjusting screw changes only the stroke end position and has no effect on the cylinder's force output.
The SCJ includes a rear-cap adjusting screw that lets you shorten the stroke end by up to 40 mm on this model, providing on-machine flexibility for setup and wear compensation. The fixed-stroke SC series has no such adjustment. Both share the same bore, rod, and force characteristics, but the SCJ body is slightly longer to house the screw mechanism.
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