Airtac SCJ50 Standard Cylinder SCJ50X400-20S
The AirTAC Airtac SCJ50 Standard Cylinder SCJ50X400-20S 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, 400mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ50 mm
- Nominal stroke400 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM16×1.5
- CushionAdjustable, 21 mm
About the Airtac SCJ50 Standard Cylinder SCJ50X400-20S
The SCJ50X400-20S is a 50 mm bore double-acting single-rod cylinder that delivers 982 N of push force at 0.5 MPa, giving you the muscle for medium-duty positioning tasks. Its defining feature is the rear-cap adjusting screw, which lets you shorten the stroke end by up to 20 mm right on the machine—no need to swap cylinders or add external hard stops during commissioning or format changes.
This model includes a built-in magnet (-S suffix), so you can clamp CMSG/DMSG/EMSG reed or solid-state sensors directly onto the tie-rod barrel for precise end-of-stroke detection. The 20 mm rod runs in a 21 mm air cushion, and with a body length A of 194 mm plus the 400 mm nominal stroke, it fits neatly into constrained spaces while still offering a long working reach.
Airtac SCJ50 Standard Cylinder SCJ50X400-20S Technical Specifications
| Model | Airtac SCJ50 Standard Cylinder SCJ50X400-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 400 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 SCJ50X400-20S
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 50 | Bore size in mm. |
| ×400 | 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 SCJ50X400-20S Is Used
Commissioning & Setup
Fine-tune the end-stop position on a new assembly line without fabricating custom shims. The 20 mm adjustment screw lets technicians dial in the exact stroke during initial runoff.
Product Changeover
Quickly adapt a stop gate or diverter for different package sizes. The adjustable stroke eliminates mechanical rework when switching between product formats on a packaging conveyor.
Wear Compensation
Take up mechanical play in a clamping or pressing fixture over time. As tooling wears, the stroke can be lengthened slightly via the rear screw to maintain consistent contact force.
Is the Airtac SCJ50 Standard Cylinder SCJ50X400-20S the Right Cylinder?
Step up to the SCJ63X400-20S (1559 N push at 0.5 MPa) if you need a heavier force margin without increasing air pressure, or drop to the SCJ40X400-20S (628 N push) for lighter, faster-cycling loads. The SCJ is the right choice when you need to fine-tune the stroke end position in the field; if your stroke length is fixed and never changes, a standard SC50X400-S fixed-stroke cylinder is a simpler, lower-cost alternative. For a direct replacement, match the 50 mm bore, 400 mm nominal stroke, 20 mm adjust range, PT port thread, basic mounting, and the built-in magnet. At 400 mm of stroke, be mindful of side loads—if the rod is pushing an unguided mass, add an external guide rail or consider a guided cylinder to prevent rod 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 SCJ50 Standard Cylinder SCJ50X400-20S FAQ
At the maximum operating pressure of 1.0 MPa, the theoretical push force is 1767 N. At a typical plant pressure of 0.7 MPa, it delivers 1374 N of push force. The pull force is lower (825 N at 0.5 MPa) due to the area of the 20 mm piston rod.
Yes, provided the old cylinder is an AirTAC SCJ or SC with a 50 mm bore, PT ports, and a stroke of at least 400 mm. The SCJ's body is slightly longer to house the adjusting mechanism, so check the overall length. The built-in magnet allows you to reuse or add magnetic sensors for position feedback.
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