The AirTAC Airtac SCD Standard Cylinder SCD250X400S is a genuine double-acting DOUBLE-ROD air cylinder: the Ø50mm piston rod extends from BOTH end caps, giving equal effective area — and therefore equal force — in push and pull. Ø250mm bore, 400mm stroke, PT1" ports and adjustable end cushioning.
The SCD250X400S is a heavy-duty double-rod pneumatic cylinder that outputs an identical 23562 N of thrust in both extend and retract strokes at 0.5 MPa, rising to 42412 N at 0.9 MPa. This perfect force symmetry comes from the 50 mm diameter rod passing through both end caps, subtracting the same area from each side of the 250 mm bore piston. A 40 mm adjustable air cushion at each end decelerates the high-inertia load smoothly, protecting the end caps during the 400 mm travel.
This model includes a built-in magnet (-S suffix), allowing easy external mounting of CMSG, DMSG, or EMSG sensors directly on the tie-rod barrel for non-contact position feedback. The retracted body length (A dimension) is 435 mm, and the cylinder operates on standard PT ports with a G1 thread. As a genuine AirTAC product, it is engineered for demanding industrial tasks where a through-rod design provides superior guidance and the ability to attach tooling or flags to the rear rod end.
| Model | Airtac SCD Standard Cylinder SCD250X400S |
|---|---|
| Series | SCD double-rod tie-rod cylinder (ISO 6430 class) |
| Bore size | Ø250 mm |
| Rod diameter | Ø50 mm (both ends) |
| Stroke | 400 mm |
| Rod configuration | Double rod — rod through both caps |
| Acting type | Double acting |
| 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 SCD (double-rod) datasheet. Because the rod runs through both caps, the effective area is (bore² − rod²) in both directions. Confirm against the product label before installation. Thread options: PT (standard) / G.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 23562 N | 23562 N |
| 0.7 MPa | 32987 N | 32987 N |
| Max (@1.0 MPa) | 4805 kgf | |
Push and pull are EQUAL on a double-rod cylinder — both chambers lose the rod area, so effective area = (bore² − rod²) each way. Actual usable force is lower than theoretical due to friction and back-pressure; size with a safety margin.
| SCD | Double-rod tie-rod cylinder series (rod out both ends). |
|---|---|
| 250 | Bore size in mm. |
| ×400 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Related types: SC (single rod), SCJ (adjustable stroke), SCT (multi-position). SCD mounting: Basic, FA, LB, TC, TCM1. Seals: TPU standard / H = Viton / N = NBR. Thread: blank = PT, G = G thread.
The equal push-pull force and rear rod connection point make it ideal for driving a shuttle table that moves heavy pallets between two conveyor lines, using both ends of the cylinder for balanced actuation.
Delivers a consistent 42 kN of force at 0.9 MPa from both sides, suitable for a two-station pressing or clamping fixture where a tool is mounted on each rod end for sequential operations.
The built-in magnet allows CMSG/DMSG sensors to be mounted on the rear rod extension, providing end-of-stroke confirmation in a location that is shielded from the primary work zone's heat and debris.
Select the SCD250 when you need symmetric, high-force actuation exceeding 20000 N in both directions. If your load requires less force, the SCD200 bore delivers 15080 N at the same 0.5 MPa, offering a more compact and economical package. Always verify that the 400 mm stroke does not expose the 50 mm rod to excessive side loading; for applications with significant lateral forces, an external guide rail or a dedicated guided cylinder is mandatory, as the double-rod design improves guidance but is not a full side-load bearing.
For a direct replacement, match the 250 mm bore, 400 mm stroke, PT (G1) port thread, basic mounting style, and the built-in magnet configuration. This SCD double-rod cylinder is not dimensionally interchangeable with ISO 15552 profiles; it is an AirTAC tie-rod design. If your application only requires force output from one end, the single-rod SC series provides a simpler, lower-cost alternative.
Double-rod checklist
Because it is a double-rod cylinder, the push and pull forces are identical. The effective piston area is calculated by subtracting the 50 mm rod area from the 250 mm bore area. This results in 23562 N at 0.5 MPa, 32987 N at 0.7 MPa, and 42412 N at the maximum operating pressure of 0.9 MPa.
Choose the SCD when you need perfectly equal force and speed in both directions, or when you need to utilize the rear rod extension for mounting a sensor flag, a mechanical stop, or secondary tooling. The through-rod also provides better support and alignment for the piston, reducing uneven wear compared to a single-rod cylinder under the same conditions.
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