Airtac SCJ50 Standard Cylinder SCJ50X125-20S
The AirTAC Airtac SCJ50 Standard Cylinder SCJ50X125-20S 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, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ50 mm
- Nominal stroke125 mm
- Stroke adjust-20 mm
- Port sizePT1/4
- Rod threadM16×1.5
- CushionAdjustable, 21 mm
About the Airtac SCJ50 Standard Cylinder SCJ50X125-20S
The SCJ50X125-20S is a double-acting, single-rod pneumatic cylinder with a rear adjusting screw that lets you fine-tune the stroke end by up to 20 mm on the machine. With a 50 mm bore and 20 mm rod, it delivers 982 N of push force at 0.5 MPa, making it a strong mid-range actuator for tasks where the final stop position needs dialling in during commissioning or changeover.
This model includes a built-in magnet (-S suffix), so CMSG, DMSG, or EMSG sensors clamp directly onto the tie-rod barrel for reliable end-of-stroke detection. The body length A(SCJ) is 194 mm, and the standard PT1/4 ports keep plumbing simple. The adjustable cushion decelerates the piston smoothly, and the screw sets the stroke end without affecting the nominal 125 mm maximum rating.
Airtac SCJ50 Standard Cylinder SCJ50X125-20S Technical Specifications
| Model | Airtac SCJ50 Standard Cylinder SCJ50X125-20S |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 125 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 SCJ50X125-20S
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 50 | Bore size in mm. |
| ×125 | 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 SCJ50X125-20S Is Used
Commissioning Fine-Tuning
During machine setup, use the 20 mm rear screw to precisely dial in the end-stop position for a clamp or pusher without re-machining hard stops or reprogramming servo axes.
Format Changeover
On packaging lines switching between box sizes, the adjustable stroke lets operators quickly reset the cylinder's push distance to match a new product dimension, minimising downtime.
Wear Compensation
In pressing or forming operations, the screw can be advanced over time to take up slack from tooling wear, maintaining consistent contact force without replacing the actuator.
Is the Airtac SCJ50 Standard Cylinder SCJ50X125-20S the Right Cylinder?
Choose the SCJ50X125-20S when you need a 50 mm bore cylinder with a 125 mm nominal stroke and the ability to shorten the stroke end by up to 20 mm without swapping the unit. If you need more force, step up to the 63 mm bore (1559 N push at 0.5 MPa); for a lighter load, the 40 mm bore provides 628 N. This adjustable-stroke model is ideal for commissioning trials, but if your stroke is fixed and never needs field adjustment, the standard SC50X125 is a simpler, cost-effective alternative.
For a direct replacement, match the 50 mm bore, 125 mm nominal stroke, 20 mm adjust range, PT1/4 ports, and the -S magnet option. Since the rod extends 125 mm, ensure the load is guided externally if you encounter side forces, or consider a guided cylinder to protect the rod bearing from bending moments.
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 SCJ50X125-20S FAQ
At 0.5 MPa, it produces 982 N pushing and 825 N pulling. The push force is higher because the single rod reduces the piston area on the return side. At the maximum operating pressure of 1.0 MPa, the theoretical push force reaches 200 kgf.
A rear-cap screw lets you shorten the stroke end by up to 20 mm from the nominal 125 mm maximum. It sets the physical stop position, not the force or speed. You can replace a fixed-stroke SC with this SCJ if you need field adjustability, but you must match the 50 mm bore, PT1/4 ports, and the -S magnet option.
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