The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-40S 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. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X125-40 is a double-acting, single-rod pneumatic cylinder with a rear-cap adjusting screw that provides a 40 mm field-adjustable stroke range. Operating at 0.5 MPa, it delivers 628 N of push force and 528 N of pull force, making it a capable mid-range actuator for applications needing fine-tuned end-position control.
This 40 mm bore model features a 16 mm diameter piston rod, PT1/4 ports, and an M12x1.25 rod thread. The built-in magnet (denoted by the -S suffix) allows for direct mounting of CMSG/DMSG/EMSG reed or solid-state sensors along the tie-rod barrel for precise, non-contact end-of-stroke sensing.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-40S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 40 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1/4 |
| Rod thread | M12×1.25 |
| 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 | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 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. |
|---|---|
| 40 | Bore size in mm. |
| ×125 | 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.
The 40 mm adjustment screw allows technicians to quickly fine-tune the retract stroke end position on a new machine without shimming or fabricating custom hard stops, drastically reducing setup time.
In clamping or pressing fixtures, the stroke end can be periodically adjusted to compensate for tooling or pad wear, maintaining consistent clamping force and part quality over the machine's life.
On a packaging line, the adjustable stroke enables a quick change of the pusher's end position to accommodate different box sizes, eliminating the need for mechanical stop adjustments or cylinder swaps.
Select the SCJ40X125-40 when you need to precisely dial in a stroke end position during commissioning or for format changeovers, without replacing the cylinder. If your force requirement is lower, stepping down to the 32 mm bore provides 402 N of push force at 0.5 MPa. For higher demands, the 50 mm bore offers a significant jump to 982 N. If your application does not require stroke adjustability, a fixed-stroke SC40 cylinder is a simpler, more cost-effective alternative. For a direct replacement, match the 40 mm bore, 125 mm nominal stroke, 40 mm adjust range, PT port thread, and the integrated magnet. This basic mount cylinder can be upgraded with FA, LB, or TC mounting kits if needed.
Adjustable-stroke checklist
The push force is 628 N at 0.5 MPa and 1130 N at the maximum operating pressure of 0.9 MPa. The pull force is lower due to the single 16 mm rod, providing 528 N at 0.5 MPa. The theoretical maximum force at 1.0 MPa is 128 kgf.
No. Like all standard pneumatic cylinders, the SCJ is not a load-holding device. If air pressure is lost or the valve is centered, the piston can drift or drop. The adjustable screw only sets the stroke end position and does not lock the piston rod. An external mechanical lock or pilot-operated check valve is required for static load holding.
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