The AirTAC Airtac SCJ50 Standard Cylinder SCJ50X125-20 is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 20 mm range without swapping the cylinder. Ø50mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ50X125-20 is a double-acting, single-rod pneumatic cylinder with a 50mm bore and a nominal 125mm stroke, featuring a rear-cap adjusting screw that provides a 20mm field-adjustable range for the stroke end. This allows precise, on-machine tuning of the piston stop position without swapping the cylinder, making it invaluable during commissioning and for format changeovers. The push force is 982 N at 0.5 MPa, and the 20mm diameter piston rod provides robust, guided motion.
Built on the durable tie-rod SC platform, this cylinder uses a PT1/4 port and an M16x1.5 rod thread. The integrated air cushion, with a 21mm cushion length, provides smooth deceleration at the stroke end, reducing impact and noise. This genuine AirTAC component is a reliable choice for applications requiring a repeatable, yet easily modifiable, end-of-stroke position.
| Model | Airtac SCJ50 Standard Cylinder SCJ50X125-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 20 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1/4 |
| Rod thread | M16×1.5 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 21 mm |
| Max stroke | Up to 1200 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 | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 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. |
|---|---|
| 50 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -20 | 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.
The 20mm adjuster allows technicians to precisely dial in the actuator's end-stop during initial machine setup, compensating for small stack-up tolerances in the assembly without needing shims or custom brackets.
Ideal for conveyor diverters or stops handling different product sizes. The stroke end can be quickly re-adjusted by 20mm to accommodate a new box or pallet dimension, minimizing line downtime.
In clamping or pressing fixtures, the adjustable stroke can be used to take up mechanical wear on tooling or contact surfaces over time, maintaining consistent clamping force and position without replacing the cylinder.
Choose the SCJ50X125-20 when your application requires a 125mm maximum stroke but the final stop position needs to be dialed in on the machine, with up to 20mm of fine adjustment. If the 982 N push force at 0.5 MPa is insufficient, stepping up to the 63mm bore (SCJ63) provides 1559 N of push force. For applications where the stroke length is fixed and will never need adjustment, the standard SC50X125 fixed-stroke cylinder is a more economical alternative. This SCJ cylinder is a direct, form-fit replacement for another AirTAC SCJ50X125-20 with PT ports and basic mounting.
Adjustable-stroke checklist
At the standard operating pressure of 0.5 MPa, the push force is 982 N and the pull force is 825 N. The maximum push force at the 0.9 MPa operating limit is 1767 N. Because it is a single-rod cylinder, the push force is greater than the pull force.
A rear-cap screw mechanically limits the piston's stroke end within a 20mm range, setting the final extended position. It is not a locking device. When air pressure is lost or the valve is centered, the piston will not hold its position and can drift. An external mechanical lock or pilot-operated check valve is required for load holding.
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