The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X450-20S 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, 450mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X450-20S is a double-acting, single-rod pneumatic cylinder engineered for heavy-duty applications requiring precise, field-adjustable stroke end positioning. With a 250 mm bore and a 450 mm nominal stroke, this tie-rod cylinder delivers a substantial push force of 24544 N at 0.5 MPa, scaling up to 44178 N at the maximum operating pressure of 0.9 MPa. The rear-cap adjusting screw provides a 20 mm range to fine-tune the stroke end, making it ideal for commissioning large-scale machinery or accommodating wear in high-cycle systems.
This model features a built-in magnet (denoted by the -S suffix), allowing direct mounting of CMSG, DMSG, or EMSG sensors on the barrel for reliable, non-contact position sensing. The 50 mm diameter piston rod and PT1" port threads ensure robust air flow, while the 40 mm air cushion at each end provides smooth deceleration. The ISO 6430 class body has a length A of 409 mm, offering a durable and serviceable platform for demanding industrial tasks.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X450-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 450 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. |
| ×450 | 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 pressing depth in large hydraulic or pneumatic presses by adjusting the stroke end screw, ensuring consistent part dimensions without reprogramming the main controller.
Set the precise mechanical stop for roll gaps in metal forming lines. The 20 mm adjustment range allows operators to quickly compensate for roll wear or change material thickness on the fly.
Use the adjustable stroke to create a repeatable, variable end-stop for life-cycle testing of large industrial dampers, where the test stroke length must be precisely dialed in for different product variants.
Select the SCJ250 bore for high-force applications up to 24544 N of push at 0.5 MPa. If your force requirements are lower, stepping down to a 200 mm bore provides 15708 N of push, which may offer a more compact and cost-effective solution. This adjustable-stroke model is the right choice when you need to fine-tune the end position on the machine, rather than swapping cylinders for different fixed strokes.
For a direct replacement, match an AirTAC SCJ adjustable-stroke cylinder with a 250 mm bore, a 450 mm nominal stroke, and a 20 mm adjustment range, with PT port threads and a built-in magnet. At this 450 mm stroke length, be mindful of potential side-loading and rod deflection. If the application involves non-axial loads, consider integrating an external guide rail or switching to a guided cylinder to protect the rod bearings and seals from premature wear.
Adjustable-stroke checklist
The push force is 24544 N at 0.5 MPa and 44178 N at 0.9 MPa. Because it is a single-rod cylinder, the pull force is slightly lower due to the rod area, delivering 23562 N at 0.5 MPa. This is a double-acting cylinder, so force is generated in both directions.
Yes, it can replace a fixed-stroke SC cylinder of the same 250 mm bore if you need the ability to fine-tune the stroke end. The SCJ has a slightly longer body to house the adjusting screw. Ensure the replacement matches the 450 mm nominal stroke, PT port threads, and that your mounting arrangement accommodates the SCJ's body length A of 409 mm.
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