The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X75-20 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, 75mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X75-20 brings a 20 mm field-adjustable stroke range to a 40 mm bore double-acting cylinder, letting you dial in the exact end position after installation. Its 16 mm piston rod and PT1/4 ports deliver 628 N of push force at 0.5 MPa, rising to 1130 N at the 0.9 MPa maximum operating pressure.
A rear-cap adjusting screw shortens the nominal 75 mm stroke by up to 20 mm without dismounting the cylinder or adding external hard stops. The body length A(SCJ) is 185 mm, and the 21 mm air cushion at each end decelerates the piston smoothly. This model runs on 40 µm filtered air and uses the standard TPU seal for a -20 to +70 °C working range.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X75-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 75 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. |
| ×75 | 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, technicians can back out the rear screw to incrementally shorten the stroke end until the actuator stops exactly at the tooling contact point, eliminating trial-and-error shimming.
On a packaging line that runs multiple box heights, the 20 mm adjustment lets operators quickly reset the pusher stroke for each SKU without changing the cylinder or reprogramming servo positions.
As gripper pads or press tooling wear down over thousands of cycles, the adjusting screw can be turned in to recover the lost stroke length, maintaining consistent part engagement without replacing tooling.
Step up to the 50 mm bore SCJ when your application needs more than 982 N push at 0.5 MPa; step down to the 32 mm bore if 402 N is sufficient and space is tight. For applications where the stroke never needs field adjustment, the fixed-stroke SC40 series offers the same force and mounting pattern in a shorter, simpler package. If the load applies significant side force, add an external guide rail or switch to a guided cylinder.
A direct replacement must match the 40 mm bore, 75 mm nominal stroke, 20 mm adjustment range, PT1/4 port thread, and basic mounting. The SCJ40X75-20 replaces only another AirTAC SCJ adjustable-stroke cylinder with the same specifications.
Adjustable-stroke checklist
The adjusting screw only changes the stroke end position, not the force. At 0.5 MPa the cylinder pushes with 628 N and pulls with 528 N (the pull force is lower because the 16 mm rod reduces the piston area on the return side). At the maximum operating pressure of 0.9 MPa, push force reaches 1130 N.
Only if you need the adjustable feature. The SCJ40X75-20 has the same 40 mm bore, rod diameter, port size, and force output as an SC40, but the rear adjusting screw makes the body slightly longer. If you do not need field stroke adjustment, a standard SC40 is the simpler drop-in choice.
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