The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X450-20 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 SCJ250X450-20 is a heavy-duty adjustable-stroke cylinder delivering 24544 N of push force at 0.5 MPa, built on a robust tie-rod construction with a 50 mm piston rod. Its rear-cap adjusting screw provides up to 20 mm of stroke-end retraction, allowing field technicians to fine-tune the stopping position for large-scale equipment without dismounting the cylinder.
This double-acting, single-rod cylinder operates on filtered air from 0.15 to 1.0 MPa and features an adjustable air cushion (40 mm length) for controlled deceleration of high-inertia loads. The standard PT1 inch port and M42x2 rod thread suit demanding industrial power transmission, with a body length A(SCJ) of 409 mm.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X450-20 |
|---|---|
| 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 by up to 20 mm, compensating for tooling wear or material thickness variations without reprogramming the entire line.
Control the opening of a large diverter gate or chute in mining or aggregate handling. The adjustable stroke allows operators to set the exact gate opening for different material flow rates on the fly.
During the setup of a new steel fabrication or heavy machinery cell, use the 20 mm adjustment range to perfectly synchronize the cylinder's end position with the mechanical stops of a large fixture or welding arm.
Choose the SCJ250X450-20 when you need substantial force capacity and the ability to dial in the stroke end precisely during commissioning or after mechanical wear. If your application requires even higher force, the next step up is not available in this series, so consider re-evaluating the mechanical advantage; for lower force needs, the SCJ200 bore provides 15708 N push at 0.5 MPa. For a fixed stroke without the adjustment feature, the standard SC series is a simpler alternative.
At a 450 mm nominal stroke, ensure the load is guided externally to prevent excessive side-loading on the 50 mm rod, which can cause seal wear and bending. A direct replacement must match the 250 mm bore, 450 mm nominal stroke, 20 mm adjust range, PT port thread, and basic mounting configuration.
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 pull force is lower due to the 50 mm rod area). The maximum push force at the 0.9 MPa operating limit is 44178 N.
A screw mechanism in the rear cap allows you to shorten the stroke end by up to 20 mm from its nominal 450 mm maximum. This mechanical stop adjusts where the piston finishes its extension, which is ideal for fine-tuning machine setups, but it does not change the cylinder's force or speed.
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