The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X25-20 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, 25mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X25-20 is a double-acting, single-rod pneumatic cylinder with a rear adjusting screw that lets you field-trim the stroke end by up to 20 mm without swapping the unit. At 0.5 MPa it delivers 628 N push and 528 N pull, making it a capable mid-compact actuator for light pressing, clamping, and diverting tasks.
The 40 mm bore body measures 185 mm long (A dimension) and uses a 16 mm diameter rod with M12x1.25 threads. It includes a 21 mm air cushion at each end for smooth deceleration, and the PT1/4 ports keep flow paths simple for standard shop air.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X25-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 25 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. |
| ×25 | 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.
During machine bring-up, use the 20 mm adjustment screw to dial in the exact end-stop position for a sensor flag or stripper plate without re-machining brackets.
Adjust the push stroke on a packaging line diverter to handle different box widths, all from the rear cap screw, keeping changeover under a minute.
Compensate for jaw or pad wear in a repetitive clamping fixture by turning the stroke-end screw, restoring full grip force without replacing the cylinder.
Choose the SCJ40X25-20 when you need a short, field-tunable stroke in a 40 mm envelope. If your load demands more force, stepping up to the 50 mm bore gives 982 N push at the same 0.5 MPa pressure. For applications where the stroke never changes, a fixed-stroke SC40 cylinder removes the adjuster and slightly shortens the overall length.
A direct replacement must match the 40 mm bore, 25 mm nominal stroke, 20 mm adjustment range, PT ports, and basic mounting. If the cylinder is mounted horizontally with a long tooling rod, consider adding an external guide rail to protect the rod bearing from side loads.
Adjustable-stroke checklist
At 0.5 MPa the push force is 628 N and the pull force is 528 N. At the maximum operating pressure of 0.9 MPa, push force reaches 1130 N. The adjustable stroke screw does not alter these force values.
Only if you need the adjustable stroke feature. The SCJ body is slightly longer than the fixed SC to house the adjusting screw. Match the 40 mm bore, 25 mm nominal stroke, PT1/4 ports, and mounting style exactly for a drop-in fit.
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