The AirTAC Airtac SCJ63 Standard Cylinder SCJ63X125-20 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. Ø63mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ63X125-20 is a double-acting, single-rod pneumatic cylinder that puts fine stroke-end adjustment directly on the machine. Its rear-cap screw lets you shorten the stroke end by up to 20 mm without removing the cylinder, which is ideal for commissioning trials, format changeovers, or taking up mechanical wear. With a 63 mm bore, this unit delivers 1559 N of push force at 0.5 MPa and 2805 N at the maximum operating pressure of 0.9 MPa.
This adjustable-stroke model uses a 20 mm piston rod with an M16x1.5 male thread and PT1/4 ports. The integral air cushion (28 mm long) decelerates the piston quietly, and the tie-rod construction keeps the assembly serviceable. The body length A for this SCJ is 197 mm, making it slightly longer than a fixed-stroke SC of the same envelope. It is built for filtered air from 0.15 to 1.0 MPa and operates in ambient temperatures from -20 to +70 °C.
| Model | Airtac SCJ63 Standard Cylinder SCJ63X125-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø63 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 | 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. |
| -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-of-stroke position during machine commissioning without swapping cylinders or machining external hard stops, saving hours of mechanical fitting time.
Quickly adjust a stop gate or diverter stroke when packaging lines switch between product sizes, keeping changeover downtime to a minimum with a simple screw adjustment.
Take up mechanical play or seal compression over the cylinder's service life by slightly reducing the stroke end, maintaining precise positioning without replacing the actuator.
Step up to an 80 mm bore (2513 N push at 0.5 MPa) if the 1559 N output of this 63 mm unit is marginal for your load, or down to a 50 mm bore (982 N) for lighter, faster-cycling tasks. Choose this SCJ when you need to dial in the stroke end position on the machine; if the stroke is fixed and never changes, a standard SC63X125 is the simpler, lower-cost alternative. For direct replacement, match an SCJ63 cylinder with a 125 mm nominal stroke, a 20 mm adjust range, PT ports, and the same basic mounting configuration.
At a 125 mm stroke, the rod is well-supported inside the bearing, but if your application introduces any side load, add an external guide rail or switch to a guided cylinder to prevent rod bending and premature seal wear.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 1559 N and the pull force is 1402 N (the pull force is lower because the 20 mm rod reduces the effective piston area on the return stroke). At the maximum operating pressure of 0.9 MPa, the push force reaches 2805 N.
Yes, the mounting footprint and port locations are the same, but the SCJ body is slightly longer to house the adjusting screw. You must also ensure the 20 mm stroke adjustment range does not interfere with your machine cycle, as the screw only shortens the stroke from the nominal 125 mm maximum.
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