The AirTAC Airtac SCJ63 Standard Cylinder SCJ63X125-20STC 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.
This SCJ63X125-20STC is a double-acting, single-rod cylinder with a rear adjusting screw that provides up to 20 mm of field-adjustable stroke-end trimming, letting you fine-tune the piston stop without swapping the unit. With a 63 mm bore and a 20 mm rod, it delivers 1559 N of push force at 0.5 MPa (2805 N at the 0.9 MPa maximum operating pressure), fitting medium-force positioning and clamping tasks where the final stroke length must be dialled in on the machine.
The model includes a built-in magnet (-S) for CMSG/DMSG/EMSG sensors and a centre trunnion mount (TC, supplied with TCM1 bracket, order code F-SC63TC) that allows the cylinder to pivot, absorbing misalignment in swinging applications. PT ports (PT1/4), TPU seals, and a 28 mm air cushion ensure smooth deceleration across the 30-800 mm/s speed range.
| Model | Airtac SCJ63 Standard Cylinder SCJ63X125-20STC |
|---|---|
| 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.
During machine setup, the 20 mm adjusting screw lets technicians precisely dial in the stroke end for grippers or clamps, eliminating the need to shim or reposition the cylinder body.
On packaging lines, the adjustable stroke allows operators to quickly reset the push distance for different box sizes without changing the cylinder or adding external stops.
In high-cycle pressing operations, the stroke can be slightly extended over time to compensate for tooling or pad wear, maintaining consistent contact force without replacing parts.
Choose this 63 mm bore when the 50 mm bore’s 982 N push at 0.5 MPa is marginal; step up to an 80 mm bore (2513 N at 0.5 MPa) if you need roughly 60% more force. The SCJ is the right pick when you need to adjust the stroke end on-site—during commissioning, format changes, or to take up wear—without external hard stops. If the stroke length is fixed and will never need field trimming, the simpler fixed-stroke SC63X125 is a cost-effective alternative.
For a direct replacement, match an AirTAC SCJ63 with a 125 mm nominal stroke, -20 adjust range, PT ports, centre trunnion (TC) mounting, and a magnet. At 125 mm stroke, rod bending is not a primary concern under axial loads, but always centre the load on the rod axis and avoid side forces to maximise seal life.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 1559 N and the pull force is 1402 N (reduced by the 20 mm rod area). At the maximum operating pressure of 0.9 MPa, push force reaches 2805 N. Always use the pull force for retraction calculations.
Yes, if you need field-adjustable stroke. The SCJ63 body is slightly longer to accommodate the adjusting screw, but it shares the same bore, rod, port, and mounting interfaces. Ensure you match the nominal stroke, port thread, and mounting style (here, centre trunnion TC).
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