Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 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.
- BoreØ125 mm
- Stroke850 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2
- CushionAdjustable, 40 mm
About the Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20
The AirTAC SAIJ125X850-20 is a double-acting ISO 15552 profile cylinder featuring a rear stroke adjuster, designed to trim the effective travel into an 830 to 850 mm window without adding external stops. Built with a carbon steel piston rod and PT tapered port threads, it delivers a 6136 N pull force at 0.5 MPa, scaling up to 11045 N of push force at 0.9 MPa. This made-to-order 850 mm stroke unit utilizes an extruded aluminum barrel with sensor grooves machined on both sides for straightforward position feedback integration.
Because the rear adjuster functions strictly as a travel stop to fine-tune end positions during commissioning, it does not lock or hold the load without live air pressure. For applications requiring true load-holding without continuous supply pressure, operators should integrate an external rod lock or select related AirTAC series like SAIL or BSAI. This model supports pneumatic speeds between 30 and 500 mm/s and includes variable air cushions at both ends to manage deceleration across its long travel distance.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 |
|---|---|
| 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.
Theoretical Output Force (Ø125mm)
| 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.
Model Code: Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20
| 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.
Where the Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 Is Used
Heavy Machinery Changeover
Dial in the 830 to 850 mm stroke window during equipment setup to accommodate different large product sizes without physically replacing the actuator assembly.
Variable End-Stop Positioning
Utilize the rear adjusting screw to fine-tune the retracted end position during commissioning, eliminating the need to machine and bolt on custom external mechanical stops.
High-Force Pressing Operations
Leverage the 11045 N of push force available at 0.9 MPa for heavy-duty forming or clamping tasks that require precise bottoming-out depth control.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 the Right Cylinder?
Select this 125 mm bore cylinder when your machinery requires heavy thrust capabilities combined with precise variable end-positioning, stepping up from a 100 mm bore that provides 3681 N of pull force at 0.5 MPa. The 20 mm rear adjustment mechanism is ideal for product changeovers on a line, allowing operators to dial in the exact stroke length without swapping out the entire actuator. When replacing an ISO 15552 cylinder, verify the 850 mm stroke, 20 mm adjustment range, PT port threads, and the specific mounting accessory set (Basic, FA, LB, TC, FTC, TCM1, TCM2).
Given the extended 850 mm stroke length, the 32 mm diameter carbon steel rod and M27x2 rod thread provide robust rigidity, but an external guide rail is still strongly recommended to prevent excessive side-loading and rod deflection. Since this configuration lacks a magnet, it does not directly support AirTAC CMSE reed or DMSE electronic sensors without modification.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT/NPT/G)
- ✓ Magnet (-S) for sensors?
- ✓ Side load — consider a guided cylinder
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Avoid side load on the piston rod.
- check Adjust end cushion screws for smooth stops.
- check Use correct mounting accessory (FA/FB/CA/CB/LB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X850-20 FAQ
At a 0.5 MPa operating pressure, this 125 mm bore cylinder provides 6136 N of push force and 5734 N of pull force. When increasing the supply pressure to 0.9 MPa, the push output rises to 11045 N.
The rear adjuster acts as a mechanical stop that allows you to shorten the nominal 850 mm stroke by up to 20 mm, creating a usable travel window between 830 and 850 mm. It only sets the end position and does not hold the load without live air pressure.
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