Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S
The AirTAC Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S is a genuine double acting, adjustable stroke JIS-standard round-body mini air cylinder with a Ø40mm bore and 125mm stroke, 1/4" air ports and a SUS304 stainless-steel barrel for mildly corrosive environments. For the same bore and stroke it is shorter than an ISO 6432 cylinder, saving mounting space.
- BoreØ40 mm
- Stroke125 mm
- Port size1/4"
- Acting typeDouble acting, adjustable stroke
- Rod threadM14×1.5
- CushionFixed TPU bumper pads
- 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 MFJ Adjustable Mini Cylinder MFJ40X125-50S
Trimming the extend stroke by up to 50 mm on site, this double-acting MFJ40X125-50S round-body mini cylinder lets you dial in the exact end position without swapping hardware. The JIS-standard riveted construction uses a SUS304 stainless barrel with aluminium covers, yielding a shorter overall length than an ISO 6432 unit for the same 40 mm bore and 125 mm stroke. It pushes with 628.3 N at 0.5 MPa, making its safe working load roughly 377 N.
The integrated -S piston magnet supports CMSG, DMSG and EMSG reed or electronic switches for position sensing. Air connects via 1/4" ports, driving a 16 mm rod with an M14x1.5 male thread. Fixed TPU bumper pads absorb end-of-stroke impact, and the SUS304 body resists mild washdown corrosion. For loads that must stay put on air loss, add an external rod lock or pilot check valve, as the adjuster only sets travel and never brakes the piston.
Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S Technical Specifications
| Model | Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S |
|---|---|
| Series | MFJ JIS mini cylinder |
| Bore size | Ø40 mm |
| Stroke | 125 mm |
| Acting type | Double acting, adjustable stroke |
| Port size | 1/4" |
| Rod thread | M14×1.5 |
| 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 – 800 mm/s |
| Cushion | Fixed TPU bumper pads |
| Max standard stroke | Up to 500 mm |
Specifications follow the official AirTAC MF/MFC (JIS-standard) datasheet. Barrel: SUS304 stainless steel; covers: aluminum alloy (round-body, riveted rolling-packed construction). Thread options: PT (blank) / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | 739 N |
| Max (@1.0 MPa) | 128 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S
| MFJ | JIS-standard round-body mini cylinder (adjustable-stroke). |
|---|---|
| 40 | Bore size in mm. |
| ×125 | Stroke length in mm. |
| -S | Optional built-in magnet for CMSG / DMSG / EMSG sensors. |
MF-family variants: MF / MFC (double acting ±cushion), MSF / MTF (single acting push / pull), MFD / MFCD (double rod ±cushion), MFJ / MFCJ (adjustable stroke ±cushion). Back covers CA / U / CM. Mounting LB / FA / SDB / TC.
Where the Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S Is Used
Changeover Dial-In
Leverage the 628.3 N push force to shift heavy format plates, using the 50 mm adjuster to set precise extend stops for different product sizes without changing hardware.
Prototype Stroke Setup
Perfect for trial rigs where the final extend position is unknown; shorten the 125 mm stroke on the fly until the kinematics are proven, avoiding repeated cylinder swaps.
Variable Position Stops
Actuate clamping arms that need slightly different reach per job, relying on the SUS304 body and 1/4" ports to deliver consistent force in mildly corrosive environments.
Is the Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S the Right Cylinder?
When sizing these adjustable cylinders, compare both bores directly: this 40 mm version delivers 628.3 N push at 0.5 MPa, whereas the smaller MFJ32 provides 402.2 N. Choose the 40 mm bore when moving heavier jigs or defeating substantial friction, and use the 50 mm external adjuster window to fine-tune the 75 to 125 mm extend length during trial fits or line changeovers. Mounting options include LB foot, FA flange and TC trunnion (no SDB or back-cover variant exists).
Because the -S magnet is present, you can fit CMSG, DMSG or EMSG sensors directly. Remember the adjuster only shortens the extend stroke; retract remains full. The cylinder relies on fixed TPU bumpers, not an adjustable air cushion, and will drift if air pressure drops unless you lock the load externally.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT / G / NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Back cover (CA/U/CM) & mount (LB/FA/SDB/TC)
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 Do not dismantle the riveted front/back covers.
- check Use correct back cover (CA/U/CM) & mount (LB/FA/SDB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac MFJ Adjustable Mini Cylinder MFJ40X125-50S FAQ
This 40 mm bore cylinder operates at 30-800 mm/s on 1/4" ports. At 0.5 MPa it pushes 628.3 N and pulls 527.8 N; at 0.7 MPa it pushes 879.6 N and pulls 738.9 N. The theoretical maximum force is 128.1 kgf at 1.0 MPa, with a 16 mm rod and M14x1.5 male thread.
The external adjuster shortens the extend stroke by up to 50 mm, giving a usable extend window of 75-125 mm; retract remains full. The -S suffix means a piston magnet is built in for CMSG, DMSG or EMSG sensors. Fixed TPU bumpers decelerate the stroke ends, but this is not an adjustable air cushion or a mid-stroke lock.
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1-Year Warranty
Covers non-human-caused product damage.
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Standard models are processed and dispatched in 3-5 business days.
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