The AirTAC Airtac SCJ63 Standard Cylinder SCJ63X125-75 is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 75 mm range without swapping the cylinder. Ø63mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ63X125-75 is a double-acting, single-rod pneumatic cylinder that puts stroke-end fine-tuning directly on the machine. Its rear-cap adjusting screw gives you up to 75 mm of adjustment on the 125 mm nominal stroke, so you can dial in the exact stop position during commissioning, format changeovers, or after wear-in—without swapping the cylinder or adding external hard stops. With a 20 mm piston rod and PT1/4 ports, it delivers 1559 N of push force at 0.5 MPa and up to 2805 N at 0.9 MPa.
This 63 mm bore tie-rod cylinder uses an adjustable air cushion (28 mm length) to decelerate the piston quietly near stroke end. The body length A(SCJ) is 197 mm, making it a compact choice for machinery where the stroke must be field-tuned. The default configuration ships with TPU seals, PT threads, and no magnet, suiting general-purpose industrial air service from -20 to +70 °C.
| Model | Airtac SCJ63 Standard Cylinder SCJ63X125-75 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø63 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 75 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1/4 |
| Rod thread | M16×1.5 |
| 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, 28 mm |
| Max stroke | Up to 1500 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 | 1559 N | 1402 N |
| 0.7 MPa | 2182 N | — |
| Max (@1.0 MPa) | 318 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. |
|---|---|
| 63 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -75 | 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, the 75 mm adjustment range lets technicians fine-tune the actuator end position without re-plumbing or machining new stops, cutting setup time on packaging and assembly lines.
When a conveyor diverter or gate handles multiple box sizes, the rear screw adjusts the stroke end in minutes to match the new product width, eliminating mechanical stop changes.
In clamping or pressing fixtures where tooling surfaces gradually wear, the adjustable stroke end can be tweaked to restore the original clamp position without replacing the cylinder or reworking the fixture.
Choose the SCJ63 bore when your application needs roughly 1560 N of push at standard plant air (0.5 MPa). If you can accept less force in a smaller package, stepping down to the SCJ50 (982 N push at 0.5 MPa) saves space and weight; if you need more muscle, the SCJ80 provides 2513 N push at the same pressure. For this 125 mm stroke, a fixed-stroke SC63 is a simpler choice when the end position never changes, but the SCJ63X125-75 earns its place where the stroke must be tuned on-site. A direct replacement must match the 63 mm bore, 125 mm nominal stroke, 75 mm adjust range, PT port thread, and basic mounting. Because the stroke exceeds 100 mm, check for side loads—if the rod sees any radial force, add an external guide or switch to a guided cylinder to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
Because it is a single-rod cylinder, push and pull forces differ. At 0.5 MPa, push force is 1559 N and pull force is 1402 N (the rod area reduces the pull side). At the maximum operating pressure of 1.0 MPa, push reaches 3118 N. The 75 mm stroke adjustment does not change the force output—it only sets the stroke end position.
Only if you need the field-adjustable stroke feature and the mounting footprint works. The SCJ body is slightly longer than the fixed-stroke SC of the same nominal stroke to house the adjusting screw. You must match the 63 mm bore, 125 mm nominal stroke, PT1/4 ports, and your mounting style. If you currently use a flange or clevis mount, note that the SCJ does not support FB, CA, or CB accessories—only Basic, FA, LB, and TC/TCM1.
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