The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X125-30 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, 125mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X125-30 is a heavy-duty double-acting single-rod cylinder with a field-adjustable stroke end, built for applications where a 250 mm bore's 24544 N push force at 0.5 MPa is required but the end position needs fine-tuning during commissioning or changeover. The rear-cap adjusting screw provides up to 30 mm of stroke-end reduction without swapping the cylinder, while the 50 mm diameter piston rod and 40 mm cushion length handle substantial side loads and deceleration.
This ISO 6430 class tie-rod cylinder operates on filtered air from 0.15 to 1.0 MPa and uses a PT1 inch port. The body length A(SCJ) is 409 mm, and the maximum standard stroke for this bore is 1500 mm. At the maximum operating pressure of 0.9 MPa, the push force reaches 44178 N, making it suitable for pressing, clamping, and heavy material handling where the final position must be dialed in precisely.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X125-30 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 125 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. |
| ×125 | 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.
Dial in the exact bottom-dead-centre position of a large pneumatic press during setup or after tooling changes, using the 30 mm adjustment range to compensate for part thickness variations without reprogramming the machine.
Fine-tune the end stop of a heavy-duty pusher or diverter on a conveyor line handling pallets or large castings, accommodating different product sizes by adjusting the stroke end mechanically on the fly.
Adjust the final clamp position on a large welding or assembly fixture to apply consistent force to workpieces of varying thickness, using the rear screw to set the precise closure point within the 30 mm window.
Select the SCJ250X125-30 when you need the immense push force of a 250 mm bore—24544 N at 0.5 MPa—and the ability to trim the stroke end by up to 30 mm on the machine. If your force requirement is lower, stepping down to the 200 mm bore reduces push force to 15708 N at 0.5 MPa, which may be sufficient and saves space and air consumption. For applications needing a fixed, non-adjustable stroke, the standard SC250X125 is a simpler alternative.
A direct replacement must match the 250 mm bore, 125 mm nominal stroke, 30 mm adjust range, PT1 inch port thread, and basic mounting. For strokes of 125 mm, rod bending from side loads is a critical consideration at this bore size; if the load is not guided externally, pair this cylinder with a linear guide or consider a guided cylinder to protect the 50 mm rod and bearing from premature wear.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 24544 N and the pull force is 23562 N because the single rod reduces the piston area on the return stroke. At the maximum operating pressure of 0.9 MPa, the push force increases to 44178 N. The adjustable stroke screw does not alter the cylinder's force output.
You can replace a fixed-stroke SC250 with an SCJ250X125-30 if you need the 30 mm stroke-end adjustability and the mounting, port thread (PT1 inch), and magnet options match. The SCJ body is slightly longer to house the adjusting screw, so verify the extended envelope fits your machine before ordering.
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