The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-20STC 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. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X125-20STC is a 40 mm bore double-acting, single-rod cylinder with a rear-cap adjusting screw, giving you up to 20 mm of field-adjustable stroke-end control. Its 16 mm diameter piston rod delivers a push force of 628 N at 0.5 MPa, making it a solid choice for mid-range pneumatic tasks where the final stop position needs fine-tuning during commissioning or format changes.
This model comes equipped with a built-in magnet (-S) for direct mounting of CMSG/DMSG/EMSG sensors, and a centre trunnion pivot (TC) with the TCM1 bracket for swinging loads. The body length A(SCJ) is 185 mm, and the PT1/4 port with M12x1.25 rod thread ensures straightforward integration into existing circuits.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-20STC |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 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 | 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. |
| -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 stroke end by up to 20 mm during machine commissioning to perfectly align with mating parts, eliminating the need for shims or custom hard stops.
Quickly adjust the cylinder's end position for different product sizes on a packaging or sorting line, reducing downtime between batches without mechanical rework.
Compensate for gradual wear on tooling or gripper pads by slightly extending the effective stroke, maintaining consistent contact pressure and cycle performance.
Choose this 40 mm bore when the 32 mm bore's 402 N push at 0.5 MPa is insufficient, but you don't yet need the 50 mm bore's 982 N. The 20 mm adjustable stroke is ideal for dialling in an end position without swapping cylinders. If your application requires a fixed, non-adjustable stroke, the standard SC40X125 is the direct alternative.
For replacement, match the 40 mm bore, 125 mm nominal stroke, 20 mm adjust range, PT thread, and the TC centre trunnion mounting (F-SC40TC). The built-in magnet must also be matched if sensor feedback is part of your control scheme. For strokes of 125 mm, side-loading is generally manageable, but always ensure the load is guided if off-axis forces are present.
Adjustable-stroke checklist
At 0.5 MPa, the push force is 628 N and the pull force is 528 N. The pull force is lower due to the 16 mm piston rod area. The maximum push force at 0.9 MPa is 1130 N.
Yes, if you need the ability to fine-tune the stroke end. The SCJ40X125-20STC replaces an SC40X125 with the same port (PT1/4), magnet, and TC mount. The body is slightly longer to house the adjusting screw, so check your machine's clearance.
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