The AirTAC Airtac SCJ250 Standard Cylinder SCJ250X120-20 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. Ø250mm bore, 120mm nominal stroke, PT1" ports and adjustable end cushioning.
The SCJ250X120-20 is a double-acting, single-rod pneumatic cylinder from AirTAC, engineered for heavy-duty applications requiring precise, field-adjustable stroke end positioning. With a 250 mm bore and a nominal 120 mm stroke, this model delivers a substantial 24544 N of push force at 0.5 MPa, scaling up to 44178 N at the maximum operating pressure of 0.9 MPa. The rear-cap adjusting screw provides a 20 mm range to fine-tune the stroke end, making it ideal for commissioning large-scale machinery or accommodating wear in high-cycle forming and clamping operations.
This ISO 6430 class cylinder features a robust 50 mm diameter piston rod and a PT1 port for reliable high-flow connections. The body length A(SCJ) is 409 mm, and the integrated air cushion is 40 mm long, effectively decelerating heavy end-of-stroke loads. Built with a durable TPU seal as standard, it operates reliably in temperatures from -20 to +70 °C, ensuring consistent performance in demanding industrial environments.
| Model | Airtac SCJ250 Standard Cylinder SCJ250X120-20 |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Nominal stroke | 120 mm |
| Stroke adjustment | Up to 20 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1" |
| Rod thread | M42×2 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 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 | 24544 N | 23562 N |
| 0.7 MPa | 34361 N | — |
| Max (@1.0 MPa) | 5006 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. |
|---|---|
| 250 | Bore size in mm. |
| ×120 | 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 final clamping position on large hydraulic-style pneumatic presses by adjusting the stroke end by up to 20 mm, ensuring consistent pressure without over-stroking and damaging tooling or parts.
Quickly adapt the end-stop for different product sizes on heavy-duty packaging or material handling lines. The 20 mm adjustment range allows operators to switch between formats without replacing the cylinder.
During initial machine setup, use the rear screw to dial in the exact stroke end position. Over time, the same adjustment can compensate for mechanical wear in linkages or tooling, extending the system's service life.
Select the SCJ250 when your application demands the highest force output in the SCJ range, with 24544 N of push at 0.5 MPa. If your force requirements are lower, consider stepping down to the SCJ200, which provides 15708 N of push at the same pressure, potentially reducing energy consumption and physical footprint. For applications where a fixed stroke is sufficient and the adjustability is not needed, the standard SC250 cylinder is a more economical alternative. When replacing an existing unit, ensure the match is exact: an AirTAC SCJ250 with a 120 mm nominal stroke, a 20 mm adjust range, and PT port threads. For this 120 mm stroke, side-loading is typically not a primary concern, but for any application with off-center loads, an external guide rail is recommended to protect the rod and seals from premature wear.
Adjustable-stroke checklist
The push force is 24544 N at 0.5 MPa and 44178 N at 0.9 MPa. The pull force is lower due to the 50 mm rod diameter, providing 23562 N at 0.5 MPa. This force difference is a key characteristic of all single-rod cylinders.
Yes, the SCJ250X120-20 can replace an SC250X120 if you need the 20 mm stroke-end adjustment feature. The mounting footprint, port size (PT1), and overall force characteristics are identical. Ensure your machine has clearance for the rear adjusting screw mechanism, which makes the SCJ body slightly longer than the fixed-stroke SC version.
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