The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X120-20S 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, 120mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X120-20S is a double-acting, single-rod tie-rod cylinder featuring a rear-cap adjusting screw that provides up to 20 mm of field-adjustable stroke-end reduction. With a 40 mm bore and 16 mm piston rod, it delivers 628 N of push force and 528 N of pull force at 0.5 MPa, making it a compact yet powerful solution for applications where the end position must be fine-tuned during commissioning or changeovers.
This model includes a built-in magnet (S suffix), allowing direct mounting of CMSG/DMSG/EMSG reed or solid-state sensors on the barrel for reliable end-of-stroke detection without external brackets. The cylinder body length A(SCJ) is 185 mm, and it uses a PT1/4 port with an M12x1.25 rod thread, operating smoothly within a 30-800 mm/s speed range.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X120-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 120 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. |
| ×120 | 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 20 mm adjustable stroke lets technicians fine-tune the end position during initial machine setup, compensating for minor stack-up tolerances without needing to machine custom spacers or stops.
Quickly adjust the push stroke for different product sizes on a packaging line. The built-in magnet sensor confirms the new position, reducing downtime between batch runs.
In clamping or pressing fixtures, the adjusting screw can be advanced over time to take up mechanical wear on tooling or pads, maintaining consistent clamping force without replacing the actuator.
Choose the SCJ40X120-20S when you need to dial in the stroke end position on the machine without swapping the cylinder. If your force requirement is lower, the 32 mm bore SCJ (402 N push at 0.5 MPa) offers a lighter, more compact alternative; for higher force, step up to the 50 mm bore SCJ which provides 982 N push. For applications requiring a fixed, non-adjustable stroke, the standard SC series is a simpler and more economical choice.
As a direct replacement, match this model with another AirTAC SCJ adjustable-stroke cylinder of 40 mm bore, 120 mm nominal stroke, a 20 mm adjustment range, PT ports, basic mounting, and a built-in magnet. For strokes of 300 mm or more, evaluate side-loading on the 16 mm rod and consider an external guide or a guided cylinder to prevent rod bending.
Adjustable-stroke checklist
At the standard 0.5 MPa operating pressure, the cylinder generates 628 N of push force and 528 N of pull force. The maximum push force at the 0.9 MPa upper pressure limit is 1130 N.
A rear-cap screw shortens the stroke end by up to 20 mm from the 120 mm nominal maximum. It is a direct dimensional replacement for an SCJ of the same bore, stroke, and adjust range, but it cannot replace a fixed-stroke SC cylinder unless the application specifically requires the adjustable feature and the slightly longer body length.
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