The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-50STC is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 50 mm range without swapping the cylinder. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The AirTAC SCJ40X125-50STC is a double-acting, single-rod pneumatic cylinder that puts stroke-end tuning directly in your hands via a rear-cap adjusting screw. With a 40mm bore delivering 628 N of push force at 0.5 MPa (1130 N at 0.9 MPa), it handles moderate clamping, pressing, and positioning tasks where the exact end point needs field tweaking. The -50 suffix means you can shorten the nominal 125mm stroke by up to 50mm without swapping the cylinder—ideal for commissioning and format changeovers.
This model is factory-equipped with a built-in magnet (-S) for direct mounting of CMSG/DMSG/EMSG sensors, and a centre trunnion (TC) mount that lets the cylinder pivot, absorbing misalignment in swinging applications. The 16mm piston rod, PT1/4 ports, and 21mm air cushion ensure smooth, reliable cycling. Body length A(SCJ) is 185mm, making it a compact adjustable-stroke solution for space-constrained machinery.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-50STC |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 50 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. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -50 | 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 position during machine commissioning without changing hard stops. The 50mm adjustment range lets technicians dial in the exact stroke for sensors, clamps, or ejectors on a new assembly line.
Quickly adapt to different product sizes on a packaging or sorting line. Adjust the cylinder's stroke end to match a new box height or pallet width, minimizing downtime between production runs.
Take up mechanical play or seal wear in a clamping fixture over time. The rear adjusting screw allows operators to restore precise clamping force and position without disassembling the tooling.
Choose the SCJ40 bore when your application needs roughly 628 N of push force at standard plant air. If you require more force, step up to the SCJ50, which provides 982 N push at 0.5 MPa. For a fixed, non-adjustable stroke, the standard SC40 cylinder is a simpler, cost-effective alternative. This SCJ40X125-50STC is a direct replacement for any AirTAC adjustable-stroke cylinder of the same 40mm bore, 125mm nominal stroke, 50mm adjust range, PT port thread, TC centre trunnion mount, and built-in magnet. The trunnion mount (using bracket F-SC40TC) is ideal for pivoting loads, but ensure the rod end is also free to articulate. For strokes of 300mm or more, evaluate side-loading and consider an external guide or a guided cylinder to protect the rod bearing.
Adjustable-stroke checklist
At 0.5 MPa, the cylinder provides 628 N of push force and 528 N of pull force. The push force is higher because the single piston rod reduces the effective area on the return stroke. Maximum operating force at 0.9 MPa is 1130 N push.
A rear-cap screw sets the stroke end position, shortening the nominal 125mm stroke by up to 50mm. It does not adjust speed or force. This model is a direct drop-in replacement for any AirTAC SCJ cylinder with a 40mm bore, 125mm nominal stroke, 50mm adjust range, PT ports, centre trunnion mount, and magnet.
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