Airtac SCJ40 Standard Cylinder SCJ40X250-20STC
The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X250-20STC 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, 250mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ40 mm
- Nominal stroke250 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM12×1.25
- CushionAdjustable, 21 mm
About the Airtac SCJ40 Standard Cylinder SCJ40X250-20STC
The SCJ40X250-20STC is a double-acting, single-rod pneumatic cylinder with a field-adjustable stroke, giving you up to 20 mm of end-position fine-tuning via the rear-cap screw. With a 40 mm bore and 16 mm rod, it delivers 628 N of push force at 0.5 MPa, making it a capable mid-range actuator for tasks that need repeatable, tweakable positioning.
This model is factory-configured with a built-in magnet (-S) for direct mounting of CMSG/DMSG/EMSG sensors and a centre trunnion (TC) pivot mount, supplied with the TCM1 bracket for swinging-load applications. The standard TPU seals and PT threads suit general industrial environments, and the 21 mm air cushion protects the end cap during high-cycle operation.
Airtac SCJ40 Standard Cylinder SCJ40X250-20STC Technical Specifications
| Model | Airtac SCJ40 Standard Cylinder SCJ40X250-20STC |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 250 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 SCJ40X250-20STC
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×250 | 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 SCJ40X250-20STC Is Used
Commissioning & Setup
The 20 mm rear adjustment screw lets technicians dial in the exact stroke end position on a new machine without fabricating custom hard stops, speeding up factory acceptance testing.
Product Format Changeover
Quickly adapt the cylinder's end position for different product sizes on a packaging line. The centre trunnion mount allows the cylinder body to pivot, accommodating the stroke change without binding.
Wear Compensation
In clamping or pressing fixtures, the adjustable stroke can be extended slightly over time to compensate for tooling or pad wear, maintaining consistent clamping force without replacing the cylinder.
Is the Airtac SCJ40 Standard Cylinder SCJ40X250-20STC the Right Cylinder?
Choose this 40 mm bore when your load requires around 628 N of push force at standard plant pressure. If you need more force, stepping up to the 50 mm bore provides 982 N of push, while the 32 mm bore offers a more compact 402 N alternative. This adjustable-stroke model is ideal for commissioning and format changes; if your stroke is permanently fixed, a standard SC40X250 cylinder is a simpler, cost-effective choice.
For a direct replacement, match the 40 mm bore, 250 mm nominal stroke, 20 mm adjust range, PT port thread, centre trunnion mounting (F-SC40TC), and the integrated magnet for sensor compatibility. At 250 mm of stroke, ensure the rod is guided externally if significant side loads are present to prevent bending and premature seal wear.
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 SCJ40X250-20STC FAQ
At 0.5 MPa, this single-rod cylinder provides 628 N of push force and 528 N of pull force. The forces are different because the rod reduces the effective piston area on the return stroke. Push force is always greater than pull force in a single-rod cylinder.
Yes, if you need the 20 mm stroke-end adjustability. The SCJ body length A is 185 mm, slightly longer than a fixed-stroke SC of the same bore. Ensure your mounting arrangement has clearance for the rear adjusting screw, and match the bore, nominal stroke, port thread, and mounting type for a compatible swap.
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