The AirTAC Airtac SCJ80 Standard Cylinder SCJ80X125-20 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. Ø80mm bore, 125mm nominal stroke, PT3/8 ports and adjustable end cushioning.
The SCJ80X125-20 brings 2513 N of push force at 0.5 MPa (4523 N at 0.9 MPa) into a field-adjustable package, letting you dial the stroke end back by up to 20 mm with the rear-cap screw. Its 25 mm rod and PT3/8 ports deliver the same thrust as a fixed-stroke SC80, but with the commissioning flexibility that eliminates external hard stops.
A 28 mm air cushion decelerates the piston quietly, and the 239 mm body length A(SCJ) keeps the envelope compact. This model ships in basic mount configuration with TPU seals and PT threads, ready to accept the SCJ mounting subset—foot, front flange, or centre trunnion—when your layout demands it.
| Model | Airtac SCJ80 Standard Cylinder SCJ80X125-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø80 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 20 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT3/8 |
| Rod thread | M20×1.5 |
| 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, 28 mm |
| Max stroke | Up to 1500 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 | 2513 N | 2268 N |
| 0.7 MPa | 3519 N | — |
| Max (@1.0 MPa) | 513 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. |
|---|---|
| 80 | 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.
During machine bring-up, dial the rear screw to set the exact retract stop for a clamp or ejector without re-plumbing or swapping cylinders, saving hours of mechanical adjustment.
On packaging lines that run multiple box sizes, the 20 mm adjuster lets operators reset the stroke end in seconds when switching between tall and short cartons.
As gripper pads or tooling tips wear down over thousands of cycles, advance the stroke end slightly via the rear screw to maintain consistent part contact without replacing the actuator.
Choose the SCJ80 when you need to tweak the retract end position during setup or after tooling wear; the 20 mm screw range covers most fine-adjustment tasks. If 2513 N push at 0.5 MPa is borderline, stepping up to the SCJ100 delivers 3927 N, while dropping to the SCJ63 gives 1559 N—match the force to your moving mass and cycle rate. For a fixed, non-adjustable stroke the standard SC80 is lighter and simpler; if the rod sees side load, add an external guide or switch to a guided cylinder.
Direct replacement requires matching the 80 mm bore, 125 mm nominal stroke, 20 mm adjust range, PT ports, and the same SCJ mounting accessory. At 125 mm stroke the rod is well supported, but for strokes above 300 mm always check rod buckling and consider a guide unit.
Adjustable-stroke checklist
At 0.5 MPa the push force is 2513 N and pull force is 2268 N (the rod area reduces the pull side). At the maximum operating pressure of 0.9 MPa, push reaches 4523 N. The theoretical force at 1.0 MPa is 513 kgf, though 1.0 MPa is the proof pressure limit, not a continuous operating point.
The SCJ80 is slightly longer due to the rear adjusting mechanism (body length A is 239 mm) and the mounting accessory codes differ—SCJ uses a subset: Basic, FA, LB, TC/TCM1. You can replace an SC80 with an SCJ80 if the extra length fits and you match the bore, nominal stroke, port thread, and mounting style. The adjustable screw only sets the stroke end; it does not change the force or speed.
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