Airtac SCJ50 Standard Cylinder SCJ50X690-20S
The AirTAC Airtac SCJ50 Standard Cylinder SCJ50X690-20S 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. Ø50mm bore, 690mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ50 mm
- Nominal stroke690 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM16×1.5
- CushionAdjustable, 21 mm
About the Airtac SCJ50 Standard Cylinder SCJ50X690-20S
The SCJ50X690-20S is a double-acting, single-rod pneumatic cylinder with a 50 mm bore and a nominal 690 mm stroke, giving you 982 N of push force at 0.5 MPa. Its defining feature is the rear-cap adjusting screw, which lets you fine-tune the stroke end position by up to 20 mm in the field—ideal for dialing in precise stopping points during commissioning or changeovers without swapping the cylinder.
This model includes a built-in magnet (-S suffix), so you can directly mount CMSG/DMSG/EMSG reed or solid-state sensors on the barrel for reliable end-of-stroke detection. The 20 mm rod with M16x1.5 threads and PT1/4 ports handles the load, while the adjustable air cushion decelerates the piston smoothly over the final 21 mm of travel.
Airtac SCJ50 Standard Cylinder SCJ50X690-20S Technical Specifications
| Model | Airtac SCJ50 Standard Cylinder SCJ50X690-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 690 mm |
| Stroke adjustment | Up to 20 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1/4 |
| Rod thread | M16×1.5 |
| 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 (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 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 SCJ50 Standard Cylinder SCJ50X690-20S
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 50 | Bore size in mm. |
| ×690 | 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 SCJ50 Standard Cylinder SCJ50X690-20S Is Used
Commissioning & Setup
The 20 mm adjustment screw allows technicians to quickly dial in the exact stroke end position on a new machine without needing to fabricate custom hard stops or swap out cylinders.
Format Changeovers
On packaging lines, the stroke can be easily re-adjusted to accommodate different product sizes or box dimensions, minimizing downtime between production runs.
Wear Compensation
In clamping or pressing applications, the adjustable stroke can be used to take up mechanical wear in tooling or workpieces over time, maintaining consistent contact force.
Is the Airtac SCJ50 Standard Cylinder SCJ50X690-20S the Right Cylinder?
Step up to the 63 mm bore SCJ if your application needs more force; the SCJ63 delivers 1559 N of push at 0.5 MPa. For tasks where the stroke is fixed and never needs field adjustment, the standard SC series is a simpler, more cost-effective choice. This SCJ50X690-20S is a direct dimensional replacement for another AirTAC SCJ50 with the same 690 mm nominal stroke, 20 mm adjust range, PT ports, and built-in magnet.
At a 690 mm stroke, rod buckling and side loading become critical considerations. Ensure the load is guided externally and aligned axially with the rod to prevent bending. If this is not practical, a guided cylinder or external linear guide should be used.
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 SCJ50 Standard Cylinder SCJ50X690-20S FAQ
At the standard operating pressure of 0.5 MPa, the theoretical push force is 982 N and the pull force is 825 N. The push force is greater because the rod reduces the effective piston area on the return stroke. The maximum force at 0.9 MPa is 1767 N push.
It is a direct dimensional replacement for another AirTAC SCJ50 adjustable-stroke cylinder with a 690 mm nominal stroke, a 20 mm adjustment range, PT ports, and a magnet. Always verify that the port size, mounting style, and sensor type match your existing setup.
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