The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-30 is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 30 mm range without swapping the cylinder. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X125-30 is a double-acting, single-rod pneumatic cylinder that puts stroke-end fine-tuning directly in your hands. Its rear-cap adjusting screw provides a 30 mm adjustable range, letting you dial in the exact 125 mm nominal stroke endpoint on the machine without swapping the cylinder or adding external hard stops. With a 16 mm diameter rod and M12x1.25 rod thread, this 40 mm bore actuator delivers 628 N of push force at 0.5 MPa, scaling up to 1130 N at its 1.0 MPa maximum operating pressure.
This genuine AirTAC SCJ unit uses a tie-rod construction with a PT1/4 port and a 21 mm adjustable air cushion for smooth, controlled deceleration. The body length A(SCJ) is 185 mm, making it a compact choice for inline mounting where stroke adjustment is required during commissioning or product changeovers. It operates on 40 µm filtered air across a standard temperature range of -20 to +70 °C with a speed range of 30-800 mm/s.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-30 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 30 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.
| 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.
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -30 | 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.
The 30 mm adjustment screw lets technicians quickly fine-tune the stroke end position during initial machine setup, eliminating the need to machine custom stops or trial multiple fixed-stroke cylinders.
On packaging or assembly lines, operators can adjust the cylinder's stroke to accommodate different product sizes or pallet dimensions without mechanical disassembly, reducing downtime between batches.
In clamping or pressing applications, the adjustable stroke can be extended slightly over time to compensate for tooling or pad wear, maintaining consistent contact force without replacing the actuator.
Step up to the 50 mm bore SCJ if your application needs more force—the SCJ50 series provides 982 N of push at 0.5 MPa. For applications that do not require stroke adjustability, a fixed-stroke SC40X125 cylinder offers the same force output in a slightly shorter body. If your load must be guided to prevent rod rotation or absorb side forces, consider pairing this cylinder with external guide rods or switching to a guided cylinder series. For a direct replacement, match the 40 mm bore, 125 mm nominal stroke, 30 mm adjust range, PT port thread, and basic mounting configuration. Ensure the replacement uses the same M12x1.25 rod thread and 16 mm rod diameter to maintain mechanical compatibility.
Adjustable-stroke checklist
At 0.5 MPa, this single-rod cylinder generates 628 N of push force and 528 N of pull force. The push force is higher because pressure acts on the full 40 mm bore area, while the pull force subtracts the 16 mm rod area. At the maximum operating pressure of 1.0 MPa, the theoretical push force reaches 128 kgf.
Yes, if you need field-adjustable stroke. The SCJ40X125-30 shares the same 40 mm bore, PT1/4 port, and mounting footprint as the SC series, but its body is slightly longer to house the rear adjusting screw. The 30 mm adjust range allows you to shorten the stroke end from the nominal 125 mm, a feature the fixed-stroke SC does not offer.
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