Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S
The AirTAC Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S is a genuine double acting, adjustable stroke ISO 21287 compact air cylinder with a Ø125mm bore and 300mm stroke, 1/4" air ports and a hard-anodized aluminium body. Its short compact envelope saves about 50% of the mounting length of an ISO 15552 profile cylinder.
- BoreØ125 mm
- Stroke300 mm
- Port size1/4"
- Acting typeDouble acting, adjustable stroke
- Rod threadM16×2.0
- CushionFixed TPU bumper (both ends)
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S
The ACEJ125X300-40S is a double acting ISO 21287 compact cylinder with an adjustable extend stroke: an external stop screw trims the 300 mm stroke by up to 40 mm on site, giving a usable range of 260-300 mm. At 125 mm bore it pushes 6135.9 N and pulls 5890.5 N at 0.5 MPa, rising to 8590.3 N at 0.7 MPa - enough for heavy clamping, pressing and lifting duties. As a rule of thumb, plan on roughly 3680 N (about 375 kg) of real work at 0.5 MPa rather than the full rating.
The short ISO 21287 body saves about 50% of the mounting length of an ISO 15552 profile cylinder, so this 125 mm bore fits deep dies and heavy gantries where a full-length body will not. A fixed TPU bumper at each end absorbs end-of-stroke energy, the hard-anodized aluminium body runs on an S45C hard-chrome plated 25 mm rod, and this -S model carries the optional magnet so CMSE / DMSE switches can report end positions. Speed range is 30-500 mm/s.
Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S Technical Specifications
| Model | Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S |
|---|---|
| Series | ACEJ compact cylinder |
| Standard | ISO 21287 |
| Bore size | Ø125 mm |
| Stroke | 300 mm |
| Acting type | Double acting, adjustable stroke |
| Port size | 1/4" |
| Rod thread | M16×2.0 |
| 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 | Fixed TPU bumper (both ends) |
| Max standard stroke | Up to 300 mm |
Specifications follow the official AirTAC ACE-series (ISO 21287) datasheet. Body: hard-anodized aluminium alloy; piston rod: S45C carbon steel with hard-chrome plating. Rod type: female thread (blank) or male thread (B). Thread options: PT (blank) / G. A built-in magnet is OPTIONAL — add the -S code to fit CMSE / DMSE position sensors.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5890 N |
| 0.7 MPa | 8590 N | 8247 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 ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S
| ACEJ | ISO 21287 compact cylinder (adjustable-stroke). |
|---|---|
| 125 | Bore size in mm. |
| ×300 | Stroke length in mm. |
| -40 | Adjustable stroke window (mm the extend stroke can be shortened on site). |
| S | Optional built-in magnet for CMSE / DMSE sensors (omit for no magnet). |
| B | Rod type: B = male thread; blank = female thread. |
ACE-family variants: ACE (double acting), ASE / ATE (single acting push / pull), ACED (double rod), ACEJ (adjustable stroke), TACE / TACED (non-rotating twin-guide yoke). Mounting accessories: FA / FB flange, LB foot, CA / CB clevis, CR, SDB pivot, FTC; plus I and Y knuckles. Thread PT (blank) / G.
Where the Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S Is Used
Heavy press and forming fixtures
With 6135.9 N push at 0.5 MPa (about 375 kg of usable work), the 125 mm bore drives stamping and forming fixtures where the 260-300 mm adjustable range lets you dial the ram stop to the die height.
Pallet and die cart lifting stations
The vertical-lift equivalent of the push force is about 625 kg, or roughly 312 kg with a 2:1 margin - suited to raising die carts and pallet stops in automotive and warehouse automation.
Steel and aluminium processing gates
In mills and foundries, the short ISO 21287 body slots into guarded gate and diverter frames, and the fitted -S magnet feeds CMSE / DMSE switch signals to the PLC for open/closed confirmation.
Is the Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S the Right Cylinder?
Size against neighbours: the 100 mm bore pushes 3927.0 N at 0.5 MPa, while stepping up is not possible within the range - 125 mm is the largest ACEJ bore at 6135.9 N. If your load needs more than about 375 kg of usable force at 0.5 MPa, this is the top of the series. The stop screw only shortens the extend stroke and is a mechanical end stop, not a mid-stroke lock: on air loss the piston still drifts, so add a separate holding valve for suspended loads. FA flange or LB foot mountings bolt to the ISO 21287 face, and the female M16x2.0 rod thread accepts standard rod knuckles. PT ports; G thread available on request.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Short stroke fits the compact body
- ✓ Port/thread type (PT / G)
- ✓ Add -S if you need the magnet for sensors
- ✓ Rod type (female / male B) & mount (FA/LB/CA)
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Compact body: keep the stroke short and avoid side load on the rod.
- check Do not dismantle the threaded front/back covers.
- check Keep speed within the rated range; the TPU bumper absorbs stroke-end energy.
- check Installation by qualified personnel per AirTAC docs.
Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X300-40S FAQ
At 0.5 MPa it pushes 6135.9 N and pulls 5890.5 N; at 0.7 MPa push is 8590.3 N and pull 8246.7 N; theoretical maximum is 1251.4 kgf at 1.0 MPa. The -40 code sets a 40 mm adjustment window: an external stop screw shortens the 300 mm extend stroke to any length from 260 to 300 mm. It is a mechanical end stop only - it never holds a load on air loss. Operating pressure is 0.15-1.0 MPa (22-145 psi), proof 1.5 MPa (215 psi), speed 30-500 mm/s, air filtered to 40 um, temperature -20 to +70 C.
The ISO 21287 compact body saves about 50% of the mounting length of an ISO 15552 profile cylinder, which matters at 300 mm stroke in guarded or die-limited space. A fixed TPU bumper at each end absorbs end-of-stroke energy. This model carries the optional -S magnet, so CMSE / DMSE reed or solid-state switches mount in the body slots for end-position detection; without the -S code there is no magnet. Mounting options include FA flange and LB foot, with I and Y rod knuckles for the M16x2.0 female thread.
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