
The AirTAC Airtac PBJ Adjustable Pen-Type Cylinder PBJ12X125-50S is a double-acting, double-rod pen-size mini cylinder whose rear rod carries a stroke adjuster. On a Ø12mm bore it gives a nominal 125mm stroke with a 50mm fine-adjustable window — settable from 75 to 125mm, so you set the end position without changing hardware.
The AirTAC PBJ12X125-50S is a double-acting, double-rod pen-size mini cylinder with a 50mm adjustable stroke window. A rear M5x0.8 adjuster screw shortens the retract end, giving an effective stroke range of 75-125mm from the 125mm nominal length.
Built with a SUS304 stainless barrel and a slim 12mm body, it saves space in tight jigs and end-of-arm tooling. The M5x0.8 air port and Ø5mm rod keep the envelope small, while the built-in magnet (-S) supports reed or electronic switches. A fixed TPU bumper cushions the extend and retract ends.
| Model | Airtac PBJ Adjustable Pen-Type Cylinder PBJ12X125-50S |
|---|---|
| Series | PBJ JIS pen-size adjustable-stroke cylinder |
| Bore size | Ø12 mm |
| Rod diameter | Ø5 mm |
| Nominal stroke | 125 mm |
| Adjustable window | 50 mm (75–125 mm) |
| Adjuster thread | M5×0.8 |
| Port size | M5×0.8 |
|---|---|
| Operating pressure | 0.15 – 0.7 MPa |
| Proof pressure | 1.2 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 50 – 800 mm/s |
| Cushion | Elastic bumper (both ends) |
| Max standard stroke | Up to 200 mm |
PBJ is a double-rod cylinder: the rear rod carries the stroke adjuster, which sets the stroke end within the adjustable window. Confirm the set position against the product label before installation.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 46.7 N | 46.7 N |
| 0.7 MPa (max) | 65.4 N | 65.4 N |
The rear rod passes through the rear cover, so both piston faces lose rod area: push is shown at the annular-area value (conservative), lower than a single-rod PB push of the same bore. Size with a friction margin.
| PBJ | JIS pen-size adjustable-stroke mini-cylinder series. |
|---|---|
| 12 | Bore size in mm. |
| ×125 | Nominal stroke length in mm. |
| -50 | Adjustable-stroke window in mm (10/20/30/40/50/75/100). |
| S | Built-in magnet for magnetic-switch position sensing (omit = no magnet). |
Fixed body — no separate back-cover code. Mounting accessories: LB, FA. Related PB-family variants: PB (fixed stroke), PBD (double rod), PBR (front-mount).
Dial in the exact retract distance during product changeovers. Set the rear screw anywhere from 75 to 125mm without swapping hardware.
Tune press depth on the machine.
Use the 50mm window to test multiple retract stops during prototyping. The fixed TPU bumper cushions the end of travel.
Remember that only the retract position is field-settable via the rear screw—the extend end remains fixed. Always re-tighten the lock nut after tuning to prevent vibration drift.
Confirm your ordering essentials: 12mm bore, 125mm nominal stroke, -50mm window, built-in S magnet, and any LB or FA mounting hardware. Because the rod is a slender Ø5mm over a 125mm stroke, add an external guide or linear bearing for any off-axis loads to prevent side-load damage.
Quick checklist
The effective stroke range is 75-125mm (nominal 125mm minus up to 50mm). Adjusting the stroke does not alter these force figures.
A rear M5x0.8 screw shortens the retract end only; the extend end is fixed. You must re-tighten the lock nut after setting to prevent vibration drift. The cylinder does not hold position on air loss—the piston drifts, so an external rod lock or stop is required for fail-safe holding.
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