The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-30 is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 30 mm range without swapping the cylinder. Ø250mm bore, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-30 is a double-acting, single-rod pneumatic cylinder with a field-adjustable stroke end, built on a robust tie-rod design. Its 250 mm bore generates a substantial 24544 N of push force at 0.5 MPa, while the rear adjusting screw provides up to 30 mm of stroke-end retraction, letting you fine-tune the stopping position without swapping the cylinder or adding external hard stops.
This ISO 6430 class big-bore actuator uses a 50 mm piston rod and a PT1" port, with an adjustable air cushion that decelerates the 400 mm stroke load over a 40 mm cushion zone. The body length A(SCJ) is 409 mm, and the maximum standard stroke for this bore is 1500 mm, making it a workhorse for large-scale industrial positioning tasks.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-30 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 mm |
| Stroke adjustment | Up to 30 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. |
| -30 | 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 retraction stop on a large forming press to accommodate different material thicknesses or tooling wear, using the 30 mm adjustment range to maintain precise part dimensions without reprogramming the press control.
Adjust the closed position of a heavy material-handling gate or diverter chute on a conveyor line. The screw allows operators to compensate for seal wear or linkage play over time, ensuring a perfect seal every cycle.
During factory acceptance testing of a large automation cell, use the adjustable stroke to precisely match the cylinder's end position to the mechanical interface of a weld fixture or assembly nest, eliminating the need for custom-machined shims.
Choose the SCJ250 when your application demands high thrust in the 24544 N class at 0.5 MPa and you need to dial in the stroke end during commissioning or changeovers. If your force requirement is lower, stepping down to the 200 mm bore SCJ200 reduces push force to 15708 N at the same pressure. For applications where the stroke must never be altered after setup, the fixed-stroke SC250 is a simpler alternative.
At a 400 mm nominal stroke, consider the potential for side-loading on the 50 mm rod. If the load is not guided externally, an external guide rail or a guided cylinder should be used to prevent rod bending and premature seal wear. This model is a direct replacement for another AirTAC SCJ250X400-30 with PT ports and basic mounting.
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 because the 50 mm 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.
The key difference is the rear adjusting screw on the SCJ250, which allows you to shorten the stroke end by up to 30 mm in the field. The standard SC250 has a fixed, non-adjustable stroke. The SCJ is ideal for applications needing fine-tuning, while the SC is better for fixed, repeatable strokes where adjustability is not required.
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