The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X300-20 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. Ø40mm bore, 300mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X300-20 is a double-acting, single-rod pneumatic cylinder that puts fine stroke tuning directly on the machine. A rear-cap adjusting screw lets you shorten the stroke end by up to 20 mm without removing the cylinder, making it ideal for commissioning trials, format changeovers, or taking up wear on tooling. With a 40 mm bore and 16 mm rod, it delivers 628 N of push force at 0.5 MPa, rising to 1130 N at 0.9 MPa.
This is a tie-rod cylinder, not an ISO 15552 profile unit, so dimensional interchangeability is limited to another AirTAC SCJ of the same configuration. The body length A(SCJ) is 185 mm, and the standard PT1/4 ports keep plumbing simple. The adjustable cushion decelerates the piston smoothly, but the screw itself is a stroke-end setter—it does not lock the rod or hold a load if air pressure is lost.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X300-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 300 mm |
| Stroke adjustment | Up to 20 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. |
| ×300 | 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.
Fine-tune the end position of a 300 mm stroke actuator during machine build without swapping cylinders or machining external hard stops.
Adjust the stroke end to compensate for gradual wear on gripper pads or tooling tips, maintaining consistent part contact over thousands of cycles.
Quickly adapt a pusher or diverter stroke for different product sizes on a packaging line by turning the rear screw instead of changing the cylinder.
Choose the SCJ40X300-20 when you need a mid-range force actuator with a stroke you can dial in on the fly. If your load demands more push, stepping up to the 50 mm bore (SCJ50, 982 N push at 0.5 MPa) adds force without a large footprint increase. For a fixed, non-adjustable stroke, the standard SC series is a simpler, lower-cost alternative. This model is a direct replacement for an existing AirTAC SCJ40 with a 300 mm nominal stroke, 20 mm adjust range, PT ports, basic mounting, and no magnet. At 300 mm of stroke, be mindful of side loads—if the rod is not guided externally, consider adding a guide unit or switching to a guided cylinder to prevent rod bending.
Adjustable-stroke checklist
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 push force reaches 1256 N. Because it is a single-rod cylinder, the push force is always greater than the pull force due to the rod area on the return side.
Yes, if you need the adjustable stroke feature. The SCJ40X300-20 matches the bore and nominal stroke of an SC40x300, but the body is slightly longer to house the adjusting screw. Ensure your mounting arrangement can accommodate the 185 mm body length and that the 20 mm adjustment range meets your process needs.
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