The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-20 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. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X125-20 is a double-acting, single-rod pneumatic cylinder that puts field-adjustable stroke control directly on the machine. A rear-cap adjusting screw lets you shorten the stroke end by up to 20 mm without removing the cylinder, which is ideal for commissioning fine-tuning, format changeovers, or taking up mechanical wear over time. The 40 mm bore delivers 628 N of push force at 0.5 MPa, moving a 16 mm diameter piston rod.
This model features a nominal 125 mm stroke and a 21 mm air cushion at each end for smooth deceleration. The tie-rod body construction has an overall length of 185 mm, making it a compact choice for space-constrained adjustable-stroke applications. Operating pressure spans 0.15–1.0 MPa, and the standard TPU seals work reliably from -20 to +70 °C.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-20 |
|---|---|
| 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 end position of a stopper or clamp during machine bring-up. The 20 mm screw adjustment allows precise mechanical setting without reprogramming or shimming.
Quickly adapt a diverter gate or pusher stroke for different box sizes on a packaging line. Operators can adjust the stroke end in seconds with a wrench.
In high-cycle pick-and-place units, use the adjusting screw to take up slack from pad or gripper wear, maintaining consistent contact pressure without replacing parts.
Choose the SCJ40 bore when your application needs roughly 628 N of push force at standard plant air. If you need more force, stepping up to the SCJ50 provides 982 N push at the same 0.5 MPa. For applications that do not require field adjustment of the stroke, the fixed-stroke SC40 cylinder is a simpler, cost-effective alternative. This SCJ40X125-20 is a direct dimensional replacement for another AirTAC SCJ adjustable-stroke cylinder of the same 40 mm bore, 125 mm nominal stroke, 20 mm adjust range, and PT port thread.
At a 125 mm stroke, the 16 mm rod is well-supported within the cylinder; however, if the load applies a significant side force, consider adding an external linear guide. For applications needing a built-in magnet for sensor mounting, order the -S variant.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 628 N and the pull force is 528 N (the difference is due to the 16 mm rod area). The maximum push force at the 0.9 MPa operating limit is 1130 N.
The SCJ40 body is slightly longer to house the adjusting screw. It will fit if you have clearance at the rear cap. The port size (PT1/4), rod thread (M12x1.25), and mounting accessories (FA, LB, TC) are identical to the SC40 series.
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