The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-20S 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. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The AirTAC SCJ40X125-20S is a double-acting, single-rod pneumatic cylinder that delivers 628 N of push force at 0.5 MPa, making it a solid choice for medium-duty positioning tasks. Its defining feature is a rear-cap adjusting screw, which allows the stroke end position to be fine-tuned on the machine by up to 20 mm without swapping the cylinder, perfect for commissioning and format changeovers. The built-in magnet (suffix -S) lets you clamp CMSG or DMSG sensors directly onto the 16 mm rod's tie-rod barrel for reliable end-of-stroke sensing.
This model has a nominal stroke of 125 mm and a body length A of 185 mm, with an M12x1.25 rod thread and PT1/4 ports. The air cushion is 21 mm long, providing smooth deceleration at the end of travel. With a maximum operating pressure of 1.0 MPa, the push force reaches 1130 N. The SCJ40 series is a genuine AirTAC product, designed for reliable field adjustability in a compact tie-rod package.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 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 | 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. |
| -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.
Fine-tune the 125 mm stroke end in 20 mm increments during machine commissioning to perfectly align a stop position without needing to re-plumb or swap the cylinder.
Quickly adjust the pusher stroke on a packaging line when changing product sizes, using the rear screw to set the new end position and the magnet for sensor confirmation.
Take up mechanical wear in a clamping or pressing fixture over time by advancing the stroke end screw, maintaining consistent force application without replacing parts.
Choose the SCJ40 when you need field-adjustable stroke in the 40 mm bore class. If your application requires more force, stepping up to the SCJ50 provides a 982 N push at 0.5 MPa, while a step down to the SCJ32 offers 402 N. For applications where the stroke is fixed and never needs adjustment, the standard SC40 is a simpler, direct alternative. This SCJ40X125-20S is a direct replacement for another AirTAC SCJ adjustable-stroke cylinder of the same 40 mm bore, 125 mm nominal stroke, 20 mm adjust range, PT ports, and built-in magnet.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 628 N and the pull force is 528 N. The pull force is lower because the 16 mm piston rod reduces the effective area on the return stroke. At the maximum operating pressure of 0.9 MPa, the push force is 1130 N.
Yes, if you need the ability to fine-tune the stroke end. The SCJ40 shares the same bore, rod, and port dimensions as the SC40 but adds a rear adjusting screw. Ensure the 20 mm adjustment range and the slightly longer body length (A=185 mm) fit your machine's envelope.
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