The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X300-20S 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, 300mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X300-20S is a heavy-duty double-acting single-rod cylinder with a field-adjustable stroke end, built for large-scale automation that demands fine-tuned positioning. Its 250 mm bore delivers 24544 N of push force at 0.5 MPa, while the rear adjusting screw lets you shorten the stroke by up to 20 mm without dismounting the unit—ideal for commissioning and wear take-up on large presses.
This ISO 6430 class tie-rod cylinder uses a 50 mm diameter piston rod and PT1" ports, with a 40 mm air cushion to decelerate the massive payloads it handles. The built-in magnet (S suffix) allows direct mounting of CMSG/DMSG/EMSG sensors along the barrel for reliable end-of-stroke detection, and the body length A(SCJ) is 409 mm.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X300-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 300 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. |
| ×300 | 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 pressing depth on a 250-ton forming press during die setup or after die maintenance, using the 20 mm adjustment range to dial in the exact bottom stop position.
Adjust the clamping jaw stroke on a structural steel welding fixture to accommodate different beam widths, using the rear screw to set the precise clamping point for each batch.
Set the stroke end of a large damper or gate valve actuator in a foundry, compensating for linkage wear over time without needing to replace the entire cylinder assembly.
Choose the SCJ250 when your application needs a force class around 24544 N push at 0.5 MPa; stepping down to a 200 mm bore reduces that to 15708 N, while the 250 mm bore is the largest in the SCJ range. A fixed-stroke SC cylinder is a simpler choice if you never need to alter the stroke end, but the SCJ's 20 mm adjustment range adds flexibility for process changes. For replacement, match the 250 mm bore, 300 mm nominal stroke, 20 mm adjustment range, PT port thread, and the built-in magnet. At this 300 mm stroke, ensure the rod is externally guided or use a guided cylinder to prevent bending under side loads.
Adjustable-stroke checklist
At the standard 0.7 MPa operating pressure, the push force is 34361 N. The maximum push force at 1.0 MPa is 44178 N. Pull force is lower (23562 N at 0.5 MPa) because the 50 mm rod reduces the effective piston area on the return stroke.
Yes, provided the original was an AirTAC SCJ adjustable-stroke cylinder with the same 250 mm bore, 300 mm nominal stroke, and 20 mm adjustment range. The built-in magnet must also be present if you are using magnetic sensors. The adjustable stroke end is set via the rear screw and does not change the nominal 300 mm maximum stroke.
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