Airtac M5B Basic Type Mechanical Valve M5B21008
Mechanically actuated · no coil, no pilot airThe AirTAC M5B Basic Type Mechanical Valve M5B21008 is a genuine 5/2-way basic (plunger) type control valve. A plain plunger head. Pushed by a machine part, a jig or a fingertip. It is an external control, direct-acting valve - the spool is moved mechanically, so there is nothing to wire and no pilot line to plumb. Ports are PT1/4 with a 12.0 mm2 (Cv 0.67) effective area.
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Specifications
| Model | M5B21008 |
|---|---|
| Valve type | 5/2 way, external control, direct acting |
| Actuation | Basic (plunger) type |
| Reset | Automatic (spring) restoration |
| Body series | 200 Series, single control |
| Port size | PT1/4 |
| Effective area | 12.0 mm2 (Cv 0.67) |
| Fluid | Air, filtered by a 40 um element |
|---|---|
| Pressure range | 0 - 1.0 MPa (0 - 145 psi) |
| Proof pressure | 1.5 MPa (215 psi) |
| Temperature | -20 to +70 C |
| Body material | Aluminium alloy |
| Lubrication | Not required |
| Thread standard | PT (Rc tapered) |
| Spool stroke | 2.0-3.3 mm |
Sliding-column (spool) construction, so operating force is not affected by working pressure - there is no back-pressure effect. Lubrication is not required, but once the valve has been run on lubricated air it must stay on lubricated air; AirTAC suggests ISO VG32 or equivalent. The control set is engineering plastic and must be operated by hand only - never switch it by striking it with a tool. The exhaust outlet sits on top of the body, so a silencer fits directly.
About the M5B21008
The M5B21008 is a 5/2 way mechanical control valve: external control, direct acting, and operated purely by hand or machine contact. There is no solenoid coil and no pilot port - a plain plunger is the only input, so the valve changes over the instant something presses it and springs back the moment that pressure is removed. Nothing electrical reaches this valve, which is why it suits manual stations, all-pneumatic circuits and areas where wiring is unwelcome.
This is the 200-series single-control body with 1/4 inch PT ports and a 12.0 mm2 effective orifice (Cv 0.67), the largest flow path in the M5 common family. Because the spool is a sliding-column design, the force needed to throw it does not rise with working pressure, so changeover feels identical at 0.2 MPa and at 1.0 MPa. The exhaust sits on top of the body, so a silencer screws on without re-plumbing. The metal-free plastic control set means this valve is for manual operation only - never strike the plunger with a tool.
Typical applications
Fixture clamp signal on a drilling jig
A cam plate on the jig closes over the plunger once the workpiece is located, sending a 5/2 changeover signal to advance the clamp cylinder. Spring return resets the valve automatically when the jig opens.
Fingertip jog control at a bench press
The operator presses the plunger with a finger to send the press ram forward and releases to retract. The short 2.0-3.3 mm travel gives a crisp, immediate feel with no electrical switch in the circuit.
Gate divert on a packaging line
A product pusher bar on the conveyor nudges the plunger at the divert point, switching air to the gate cylinder. Because the B set is plastic, operation stays fingertip-and-product contact only - no tool strikes.
How to choose
Choose the B plunger when a fixed machine part, jig or fingertip presses it at a known point. If you need a passing carriage to trip the valve on both passes, step up to the roller M5R21008; if the operator must hit a target without looking, the mushroom M5PM21008 gives a far larger head on the same body. The 210 body here carries 12.0 mm2 (Cv 0.67) against 9.0 mm2 (Cv 0.50) on the 1/8 inch version, so pick this port when feeding a mid-size cylinder with real speed demand.
Respect the published reversal stroke: spool travel is 2.0-3.3 mm on this model. The plunger has no separate overtravel figure, so design your striker so it cannot drive the plunger beyond roughly 3.3 mm - exceed that and you damage the valve, a limit AirTAC states explicitly.
Frequently asked questions
It is a 5/2 way external-control, direct-acting mechanical valve with a basic plunger actuator and spring (automatic) restoration. Working pressure is 0-1.0 MPa (0-145 psi), proof pressure 1.5 MPa (215 psi), and media temperature -20 to +70 C. Ports are PT1/4, the body is aluminium alloy, and the effective orifice is 12.0 mm2 (Cv 0.67). Air should be filtered to 40 um; lubrication is not required, but if lubricated air is used, keep using it.
The spool reversal stroke is 2.0-3.3 mm. That is the published working travel - drive the plunger past it and the valve is damaged, which AirTAC states explicitly in the datasheet. Mount the valve so the striker is stopped or limited once full changeover is reached, and allow a little margin for tolerance and wear over the machine's life.