The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-20S is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 20 mm range without swapping the cylinder. Ø250mm bore, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-20S is a heavy-duty double-acting, single-rod pneumatic cylinder with a field-adjustable stroke end, delivering 24544 N of push force at 0.5 MPa. Its rear-cap adjusting screw provides a 20 mm fine-tuning range, allowing engineers to dial in the exact stroke end position during commissioning or format changes without replacing the cylinder.
This ISO 6430 class tie-rod cylinder features a 50 mm diameter piston rod, a 40 mm air cushion for controlled deceleration, and a G1 port. The integrated magnet (suffix -S) allows direct mounting of CMSG/DMSG/EMSG sensors for reliable end-of-stroke detection, making it a robust solution for large-scale industrial automation tasks.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 mm |
| Stroke adjustment | Up to 20 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. |
| -20 | 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 final press depth in heavy assembly fixtures. The 20 mm adjustment screw allows operators to compensate for part tolerance variations without reprogramming the entire press cycle.
Set a precise, repeatable end-stop for large pallets or heavy components on a conveyor line. The adjustable stroke allows for quick reconfiguration when product dimensions change.
Use as a variable-stroke actuator in structural or fatigue test rigs. Engineers can easily adjust the displacement amplitude via the rear screw to set up different test parameters.
Choose the SCJ250 bore when your application requires a push force around 24544 N at 0.5 MPa. If your force requirement is lower, stepping down to the SCJ200 bore provides 15708 N of push force at the same pressure, which may offer a more compact and cost-effective solution. For applications needing a fixed, non-adjustable stroke, the standard SC series is a direct alternative.
For this 400 mm stroke length, managing side loads is critical to prevent rod bending and premature seal wear. It is strongly recommended to use an external guide rail or switch to a guided cylinder assembly to absorb lateral forces, ensuring long service life and consistent performance. A direct replacement must match the SCJ250 bore, 400 mm nominal stroke, 20 mm adjust range, PT port thread, and the -S magnet option.
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 push force is higher because the single piston rod reduces the effective area on the return stroke. At the maximum operating pressure of 0.9 MPa, the push force reaches 44178 N.
A rear-cap adjusting screw lets you shorten the stroke end by up to 20 mm from the 400 mm nominal maximum. This is ideal for on-machine fine-tuning during setup or for taking up mechanical wear over time. Choose the SCJ if you need this field adjustability; if your stroke length is fixed and never needs changing, the standard SC series is the simpler choice.
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