Airtac SCJ40 Standard Cylinder SCJ40X850-20
The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X850-20 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, 850mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ40 mm
- Nominal stroke850 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM12×1.25
- CushionAdjustable, 21 mm
About the Airtac SCJ40 Standard Cylinder SCJ40X850-20
The SCJ40X850-20 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 at 0.5 MPa, making it suitable for long-stroke positioning tasks where the final stop point needs fine-tuning during commissioning or changeovers.
This tie-rod cylinder has a body length A(SCJ) of 185 mm and uses a PT1/4 port. The adjustable cushion decelerates the piston smoothly, while the 850 mm nominal stroke stays within the 1200 mm maximum standard stroke for this bore. Operating pressure ranges from 0.15 to 1.0 MPa.
Airtac SCJ40 Standard Cylinder SCJ40X850-20 Technical Specifications
| Model | Airtac SCJ40 Standard Cylinder SCJ40X850-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 850 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 SCJ40X850-20
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×850 | 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 SCJ40X850-20 Is Used
End-Stop Tuning on Packaging Lines
The 20 mm adjustment screw lets technicians fine-tune the push stroke for different box sizes without mechanical stops, speeding up format changeovers on case erectors.
Long-Stroke Part Transfer
With an 850 mm reach and 628 N of push force, this cylinder moves components between stations. The adjustable stroke compensates for fixture wear over time, maintaining precise placement.
Commissioning & Prototyping
Engineers can quickly adjust the stroke end during machine setup and testing. The 16 mm rod and PT1/4 ports integrate easily into prototype pneumatic circuits.
Is the Airtac SCJ40 Standard Cylinder SCJ40X850-20 the Right Cylinder?
Choose the SCJ40X850-20 when you need to dial in the exact end-of-stroke position on a machine without swapping cylinders. If 628 N of push force at 0.5 MPa is insufficient, stepping up to a 50 mm bore (SCJ50 series) provides 982 N. For applications requiring a fixed, non-adjustable stroke, the standard SC series is a simpler alternative. A direct replacement must match the 40 mm bore, 850 mm nominal stroke, 20 mm adjust range, PT thread, and basic mounting. For strokes of this length, consider an external guide rail or a guided cylinder to protect the 16 mm rod from side-load deflection and bending.
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 SCJ40X850-20 FAQ
At 0.5 MPa, it produces 628 N of push force and 528 N of pull force. The push force is higher because the single rod reduces the effective piston area on the return stroke.
Yes, if the bore (40 mm), port (PT1/4), and mounting match. The SCJ adds a rear adjusting screw that shortens the stroke end by up to 20 mm, giving you field-adjustable positioning that a fixed-stroke SC cannot provide.
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