
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-50 is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø125mm bore and 850mm stroke, G1/2 air ports and adjustable end cushioning. Its standardized mounting interface makes it a drop-in replacement for other ISO 15552 cylinders in automation lines.
The AirTAC SAIJ125X850-50 is a double-acting, single-rod ISO 15552 profile cylinder featuring a rear-mounted stroke adjuster. It delivers a robust 6136N push force at 0.5MPa, making it suited to heavy-duty positioning tasks. By turning the rear screw, you can trim the effective travel back by up to 50mm, creating a precise 800-850mm usable stroke window without needing external stops.
This bore size utilizes a PT tapered G1/2 port and a 32mm carbon steel rod with an M27x2 thread, providing substantial rigidity. The extruded aluminum barrel incorporates sensor grooves on both sides for CMSE reed or DMSE electronic switches. It retains the standard variable air cushion at both ends to manage kinetic energy across its 30-500mm/s operating speed range.
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-50 |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 850 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2 |
| 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 SAI series datasheet and ISO 15552 dimensions. Confirm against the product label before installation. Port options: G (BSPP) / NPT.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 125 | Bore size in mm. |
| ×850 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Related SAI-family variants: SAID (double rod), SAIJ (adjustable stroke), SAIL (with lock), SAIF (with valve), BSAI (enclasp / clamp-lock), and SAI-S with built-in magnet. Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B); seals: TPU (blank) / Viton H / NBR N.
Dial in the exact 800-850mm end-of-stroke for large pressing or forming operations, ensuring precise contact without over-traveling the heavy load.
Adjust the retract stopper on the fly when switching between different pallet sizes on a transfer line, avoiding mechanical rebuilds.
Move heavy workpieces over 850mm of travel while using the rear screw to fine-tune the handoff position to downstream stations.
Choose this 125mm bore when a 100mm bore (providing 3927N push at 0.5MPa) lacks the necessary thrust, but a 160mm bore is physically too large. The 50mm adjustment window is ideal for fine-tuning the retract end-position during machine commissioning or product changeovers, eliminating the need to swap out a fixed-stroke SAI cylinder. Because the nominal stroke is 850mm, an external guide is recommended to prevent excessive side-loading on the rod.
This adjustable stopper only sets the travel end and does not hold the load without live air pressure; for true load-holding, consider an external rod lock, a pilot-operated check valve, or the SAIL/BSAI locking cylinder variants. To match this ISO 15552 footprint exactly, confirm the 125mm bore, 850mm stroke, PT port thread, and the reduced SAIJ mounting set (Basic, FA, LB, TC, FTC, TCM1, TCM2).
Quick checklist
At 0.5MPa operating pressure, this 125mm bore cylinder provides 6136N of push force and 5734N of pull force. At 0.7MPa, the push force increases to 8590N.
The rear adjuster acts as a mechanical stop that shortens the nominal 850mm stroke by up to 50mm, giving an effective travel window of 800-850mm. It sets the end position but does not lock the load without continuous air pressure.
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