Airtac SCJ40 Standard Cylinder SCJ40X25-20S
The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X25-20S 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, 25mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ40 mm
- Nominal stroke25 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM12×1.25
- CushionAdjustable, 21 mm
About the Airtac SCJ40 Standard Cylinder SCJ40X25-20S
The SCJ40X25-20S is a double-acting, single-rod pneumatic cylinder with a rear-cap adjusting screw that provides up to 20 mm of field-adjustable stroke-end reduction. With a 40 mm bore and 16 mm rod, it delivers 628 N of push force and 528 N of pull force at 0.5 MPa, making it a practical choice for light pressing, clamping, and ejection tasks where the final stop position needs fine-tuning during commissioning or after tooling wear.
This model includes a built-in magnet (-S suffix), allowing CMSG/DMSG/EMSG reed or solid-state sensors to be clamped directly onto the tie-rod barrel for non-contact end-of-stroke detection. The SCJ body length A is 185 mm, slightly longer than the fixed-stroke SC version due to the adjusting mechanism, and the standard PT1/4 port and M12x1.25 rod thread ensure straightforward pneumatic and mechanical integration.
Airtac SCJ40 Standard Cylinder SCJ40X25-20S Technical Specifications
| Model | Airtac SCJ40 Standard Cylinder SCJ40X25-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 25 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.
Theoretical Output Force (Ø40mm)
| 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.
Model Code: Airtac SCJ40 Standard Cylinder SCJ40X25-20S
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×25 | 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.
Where the Airtac SCJ40 Standard Cylinder SCJ40X25-20S Is Used
Commissioning & Setup
Field technicians can micro-adjust the stroke end by up to 20 mm to perfectly align a stop position during initial machine setup without needing to re-plumb or swap out the cylinder.
Wear Compensation
In repetitive pressing or clamping operations, the adjusting screw can be turned to take up mechanical wear on tooling or contact surfaces, maintaining consistent part quality over time.
Format Changeover
On small packaging or assembly lines, operators can quickly change the stroke end to accommodate different product sizes or batch formats, reducing downtime between production runs.
Is the Airtac SCJ40 Standard Cylinder SCJ40X25-20S the Right Cylinder?
Choose the SCJ40X25-20S when you need to dial in a precise stroke end on the machine without swapping cylinders or adding external hard stops. If the 628 N push force at 0.5 MPa is marginal, stepping up to a 50 mm bore (SCJ50) provides 982 N of push force. For applications where the stroke is fixed and never needs adjustment, the standard SC40 fixed-stroke cylinder is a simpler, slightly shorter alternative. A direct replacement must match the 40 mm bore, 25 mm nominal stroke, 20 mm adjust range, PT ports, basic mounting, and the built-in magnet.
Adjustable-stroke checklist
- ✓ Need to fine-tune stroke on the line?
- ✓ Nominal stroke + adjust range (-20)
- ✓ Required force at your working pressure
- ✓ Port/thread type (PT/NPT/G)
- ✓ Magnet (-S) for sensors?
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Set the rear adjusting screw, then lock it before running.
- check Adjust end cushion screws for smooth stops.
- check Use SCJ mounting accessory (FA / LB / TC / TCM1).
- check Installation by qualified personnel per AirTAC docs.
Airtac SCJ40 Standard Cylinder SCJ40X25-20S FAQ
At 0.5 MPa, the 40 mm bore generates 628 N of push force and 528 N of pull force (the pull force is lower because the 16 mm rod reduces the effective piston area on the return stroke). The maximum operating pressure is 1.0 MPa.
Yes, if you need the adjustable stroke feature. The SCJ40 body is slightly longer (A=185 mm) to house the rear adjusting screw. Ensure the 25 mm nominal stroke and 20 mm adjust range meet your motion requirements, and match the port thread (PT) and magnet option (-S) to your existing setup.
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