The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X125-50 is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 50 mm range without swapping the cylinder. Ø250mm bore, 125mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X125-50 is a heavy-duty double-acting single-rod cylinder with a field-adjustable stroke, built on a rugged tie-rod construction. Its 250 mm bore delivers a substantial 24544 N of push force at just 0.5 MPa, making it suitable for large-scale pressing, clamping, and material handling tasks where the end position must be fine-tuned during commissioning or format changes. The rear adjusting screw provides a 50 mm stroke-end reduction range without dismounting the cylinder.
This ISO 6430 class cylinder uses a 50 mm diameter piston rod and G1 inch ports for high flow. The integrated air cushion, with a 40 mm cushion length, decelerates the massive piston smoothly at the end of travel. The body length A(SCJ) is 409 mm, providing a robust platform for heavy loads while the adjustable stroke adds a layer of operational flexibility not found in fixed-stroke alternatives.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X125-50 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 50 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. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -50 | 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.
A large hydraulic-style pneumatic press uses the SCJ250X125-50 to calibrate the final pressing depth. The 50 mm adjust range lets operators compensate for tooling wear or different material thicknesses without replacing the cylinder.
In a foundry or heavy fabrication line, this cylinder ejects large castings from a mold. The adjustable stroke end allows precise control over the ejection distance, preventing damage to the part or the downstream conveyor.
For controlling the flow of bulk materials like ore or grain through large chutes, the SCJ250 acts as a damper actuator. The field-adjustable stroke sets the exact gate opening, allowing process engineers to fine-tune material feed rates on site.
Choose the SCJ250 when you need immense force combined with the ability to dial in the exact stroke end on the machine. If the 24544 N push force at 0.5 MPa is more than required, stepping down to the SCJ200 bore reduces push force to 15708 N at the same pressure. For applications needing a fixed, non-adjustable stroke, the standard SC250 series is the direct alternative. This cylinder is a direct replacement for another AirTAC SCJ250 with a 125 mm nominal stroke, 50 mm adjust range, and PT ports. For strokes of 300 mm or more, always evaluate side-loading on the 50 mm rod; an external guide rail or a guided cylinder is recommended to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
At the standard 0.5 MPa operating pressure, this cylinder provides 24544 N of push force and 23562 N of pull force. The maximum push force at the 0.9 MPa operating limit is 44178 N. The pull force is lower because the 50 mm piston rod reduces the effective area on the return stroke.
A rear-cap adjusting screw lets you shorten the stroke end by up to 50 mm in the field, giving a true adjustable range for the 125 mm nominal stroke. Use this SCJ model when you need to fine-tune the piston's stop position during machine setup, for format changeovers, or to take up mechanical wear over time. Choose a fixed-stroke SC250 cylinder if your application has a single, unchanging end position and you do not require field adjustability.
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