The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-40S is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 40 mm range without swapping the cylinder. Ø250mm bore, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-40S is a heavy-duty tie-rod cylinder that delivers 24544 N of push force at 0.5 MPa, making it suitable for pressing, clamping, and large-format positioning tasks. Its 50 mm diameter piston rod and 40 mm stroke-end adjustment screw let commissioning engineers fine-tune the end position on the machine without swapping the cylinder, which is especially valuable during format changeovers on large industrial equipment.
This model includes a built-in magnet (-S suffix), so standard CMSG, DMSG, or EMSG sensors clamp directly onto the barrel for non-contact end-of-stroke sensing. The body length A(SCJ) is 409 mm, and the integrated air cushion (40 mm length) decelerates the high-inertia load smoothly. Operating pressure spans 0.15–1.0 MPa, with a proof pressure of 1.5 MPa, and the PT1 inch port supplies ample flow for the 250 mm bore.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-40S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 mm |
| Stroke adjustment | Up to 40 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. |
| -40 | 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.
Use the 40 mm rear screw to dial in the exact pressing depth on a hydraulic-style pneumatic press, accommodating tooling wear or different part thicknesses without reprogramming the machine.
On a conveyor stop or palletising gate, quickly adjust the cylinder's extended length by up to 40 mm to handle a new product size, reducing mechanical change parts and downtime.
During initial setup of a heavy-duty welding fixture, the adjustable stroke lets you creep up on the final clamp position. Over months of service, take up pad wear by simply turning the rear screw.
Step up from the SCJ200 if the 15708 N push force at 0.5 MPa is marginal; the 250 mm bore provides a substantial jump to 24544 N. If your application does not require field-adjustable stroke, the fixed-stroke SC250 is a simpler alternative. For a direct replacement, match the 250 mm bore, 400 mm nominal stroke, 40 mm adjust range, PT thread, and the built-in magnet; the basic mounting style accepts the standard SCJ tie-rod nut mounting. Because the 400 mm stroke is long for this bore class, evaluate side-loading on the 50 mm rod—if the load is not guided, add an external linear guide or consider a guided cylinder to prevent rod bending and premature seal wear.
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 difference is due to the single 50 mm rod area). At the maximum operating pressure of 0.9 MPa, the push force reaches 44178 N. The theoretical force at 1.0 MPa is 5006 kgf.
Yes, this is a direct replacement for any AirTAC SCJ250 with a 400 mm nominal stroke, 40 mm adjust range, PT ports, and a magnet. The rear adjusting screw sets the stroke end position within a 0–40 mm range; it does not change the cylinder's force or speed. Always ensure the replacement matches the bore, stroke, adjust range, port thread, and magnet option.
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