Airtac SCJ40 Standard Cylinder SCJ40X125-40STC
The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-40STC is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 40 mm range without swapping the cylinder. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
- BoreØ40 mm
- Nominal stroke125 mm
- Stroke adjust-40 mm
- Port sizePT1/4
- Rod threadM12×1.25
- CushionAdjustable, 21 mm
About the Airtac SCJ40 Standard Cylinder SCJ40X125-40STC
The SCJ40X125-40STC puts a 40 mm bore double-acting cylinder with a rear stroke-end adjusting screw into your hands, giving you up to 40 mm of field-adjustable stroke reduction without swapping the unit. With a 16 mm piston rod and PT1/4 ports, it delivers 628 N of push force at 0.5 MPa, making it a strong mid-size actuator for tasks that need frequent end-position tweaking.
This model ships with a built-in magnet (-S) so you can directly clamp CMSG/DMSG/EMSG sensors onto the tie-rod barrel for reliable end-of-stroke detection. The centre trunnion mount (TC, supplied with TCM1 bracket, part code F-SC40TC) lets the cylinder pivot, absorbing angular misalignment in swinging or lever-driven mechanisms. Body length A is 185 mm plus stroke, and the adjustable air cushion helps decelerate the piston smoothly at both ends.
Airtac SCJ40 Standard Cylinder SCJ40X125-40STC Technical Specifications
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-40STC |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 40 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 SCJ40X125-40STC
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -40 | 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 SCJ40X125-40STC Is Used
Commissioning & Setup
Fine-tune the push stroke end position by up to 40 mm during machine commissioning without removing the cylinder or machining hard stops, speeding up the initial build phase.
Product Changeover
Quickly adjust the stroke for different product sizes on a packaging or sorting line. The trunnion mount allows the cylinder to swing freely as the stroke is dialed in for a new format.
Wear Compensation
In clamping or pressing fixtures, use the rear screw to take up mechanical wear on tooling or contact surfaces over time, maintaining consistent clamp force without reprogramming a servo.
Is the Airtac SCJ40 Standard Cylinder SCJ40X125-40STC the Right Cylinder?
Step up to the SCJ50 bore if your load needs more push force—the 50 mm bore provides 982 N at 0.5 MPa. If your application does not require the ability to change the stroke length after installation, the fixed-stroke SC40 series is a simpler, cost-effective alternative. For a direct replacement, match the 40 mm bore, 125 mm nominal stroke, 40 mm adjust range, PT port thread, centre trunnion mounting, and the integrated magnet sensor feature.
With a 125 mm stroke, ensure the rod is not subjected to high side loads; if the load is not guided, pair this cylinder with an external guide rail or switch to 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 (-40)
- ✓ 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 SCJ40X125-40STC FAQ
At 0.5 MPa, the push force is 628 N and the pull force is 528 N. At the maximum operating pressure of 1.0 MPa, the theoretical push force reaches 1256 N. The push force is always greater than the pull force because this is a single-rod cylinder.
Only if you need the adjustable stroke feature and can accommodate the slightly longer body length. The SCJ40X125-40STC matches a 40 mm bore and 125 mm nominal stroke, but you must ensure the 40 mm adjustment screw does not interfere with your machine frame and that your mounting can accept the centre trunnion.
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