The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X450-50S 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, 450mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X450-50S is a double-acting, single-rod pneumatic cylinder from AirTAC, engineered for heavy-duty applications where the stroke end position must be fine-tuned on the machine. Its rear-cap adjusting screw provides a 50 mm adjustable range, allowing operators to dial in the exact stroke end without replacing the cylinder or adding external hard stops. With a 250 mm bore, it delivers a substantial 24544 N of push force at 0.5 MPa, scaling up to 44178 N at the maximum operating pressure of 0.9 MPa.
This model features a built-in magnet, designated by the -S suffix, enabling direct mounting of CMSG, DMSG, or EMSG reed and solid-state sensors along the barrel for precise end-of-stroke or mid-stroke position feedback. The cylinder uses a 50 mm diameter piston rod with an M42x2 thread and a PT1 inch port. Its robust tie-rod construction includes an adjustable air cushion, with a 40 mm cushion length, to decelerate large inertial loads smoothly at the end of travel.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X450-50S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 450 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. |
| ×450 | 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.
In large hydraulic-style pneumatic press tools, the 50 mm adjustable stroke allows operators to compensate for varying material thicknesses or tooling wear, setting the final pressing depth with high precision without mechanical shims.
Controls a diverter gate on a heavy-duty conveyor for mining or aggregate. The adjustable stroke lets technicians fine-tune the gate's open position to match different material flow rates, optimizing throughput on the fly.
Used in a welding fixture for large structural frames, the SCJ250's stroke can be precisely dialed back by up to 50 mm to securely clamp different assembly variants without the risk of over-stroking and distorting the workpiece.
Choose the SCJ250 when your application requires a high-force actuator with the flexibility to adjust the stroke end by up to 50 mm during commissioning or format changes. If your force requirement is slightly lower, consider stepping down to the 200 mm bore SCJ200, which provides 15708 N of push force at 0.5 MPa. For applications needing a fixed, non-adjustable stroke, the standard SC series offers a simpler, more cost-effective solution. To replace this model, match the 250 mm bore, 450 mm nominal stroke, 50 mm adjust range, PT port thread, and the built-in magnet (-S). For this 450 mm stroke, be mindful of side loading; if the rod is not guided externally, consider adding a guide rod assembly or switching to a guided cylinder to prevent rod bending and ensure long seal life.
Adjustable-stroke checklist
The push force is 24544 N at 0.5 MPa and 44178 N at 0.9 MPa. The pull force is slightly lower due to the 50 mm rod area, providing 23562 N at 0.5 MPa. This is a single-rod cylinder, so push force is always greater than pull force.
No, the adjusting screw only sets the physical end-of-stroke position. It is not a locking device. Like any standard pneumatic cylinder, the SCJ250 will not hold its position if air pressure is lost or the directional valve is centered. An external mechanical lock or pilot-operated check valve is required for load holding.
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