The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X400-50S 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, 400mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X400-50S is a double-acting, single-rod pneumatic cylinder with a field-adjustable stroke, designed for heavy-duty applications where fine-tuning the end position is critical. Its rear-cap adjusting screw provides up to 50 mm of stroke-end reduction, allowing operators to dial in the exact stopping point for commissioning, format changes, or wear compensation without removing the cylinder. With a 250 mm bore, it delivers a substantial 24544 N of push force at 0.5 MPa, making it suitable for pressing, clamping, and positioning large assemblies.
This model features a built-in magnet (-S suffix), enabling direct mounting of CMSG, DMSG, or EMSG reed and solid-state sensors along the tie-rod barrel for precise end-of-stroke detection. The 50 mm diameter piston rod and PT1 inch ports ensure robust air flow for consistent cycling. As an ISO 6430 class cylinder, it operates within a 30-500 mm/s speed range and includes an adjustable air cushion for controlled deceleration. The body length A(SCJ) is 409 mm, providing a compact envelope for its power class.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X400-50S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 400 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. |
| ×400 | 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.
During the setup of a large hydraulic-style pneumatic press, the 50 mm adjustable stroke allows process engineers to precisely dial in the final pressing depth for different part batches without changing tooling or cylinder hard stops.
Controls a heavy sliding gate or diverter chute in mining or aggregate processing. The adjustable stroke end compensates for seal wear over time or allows for a slightly different open/closed position as material flow requirements change.
Used on a structural steel welding jig, the SCJ250X400-50S clamps large beams. The adjustable stroke lets the operator fine-tune the clamp's final position to accommodate different beam flange thicknesses, ensuring consistent pressure without crushing.
Select the SCJ250X400-50S when you need high force and the ability to adjust the stroke end position by up to 50 mm during setup. For applications requiring even more force, the next step up would be a custom solution beyond the standard bore range. If a fixed stroke is sufficient, the SC250X400 model offers the same force output without the adjustable mechanism. For this 400 mm stroke, be mindful of side-loading on the 50 mm rod; an external guide rail or a switch to a guided cylinder is recommended if the load is not perfectly axial. A direct replacement must match the 250 mm bore, 400 mm nominal stroke, 50 mm adjust range, PT port thread, basic mounting, and the integrated magnet sensor option.
Adjustable-stroke checklist
At the standard operating pressure of 0.5 MPa, the push force is 24544 N and the pull force is 23562 N. Because this is a single-rod cylinder, the push force is greater than the pull force due to the area of the 50 mm rod. The maximum theoretical force at 1.0 MPa is 5006 kgf.
No. The rear adjusting screw only sets the physical stroke end position; it is not a locking device or a mid-stroke brake. If air pressure is lost or the directional valve is centered, the piston will not hold its position and can drift or drop. For load holding without live air pressure, you must add an external mechanical lock, a rod brake, or a pilot-operated check valve.
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