Custom M16 to M12 Thread Adapter — Sensor Mounts, Mechanical Joints & Repair

Need an M16 to M12 adapter for a sensor or probe, a mechanical joint, or to repair a worn thread — in steel or stainless, at the right pitch? We machine it to order, including the non-standard pitches and reducing-insert forms a catalog won't carry. From a sketch, no CAD, one piece up. Get a quote →

Gland reducer, or a machined adapter?

"M16 to M12" turns up two very different parts. Most listings are cable gland reducers — thin brass or nylon with an O-ring, for stepping a cable entry down. That's the right part for an electrical gland. But if your M16/M12 joint holds a sensor, a fitting, or any load, or the pitch isn't the standard gland thread, you want a solid machined adapter. Here's the quick split:

Forms — including a thread repair insert

Because it's turned to order, the M16-to-M12 can be whatever your job needs:

• Male-female adapter — M16 male to M12 female (or reverse), to convert or extend a thread.
• Reducing insert (repair) — M16 male outside, M12 female inside; threads into a worn or oversized M16 hole and gives a fresh M12 thread.
• Double-male stud — M16 and M12 male, to join two female parts.
• Female-female coupling — to join two male threads; see female-to-female adapters, M6 to M64.

Pitch & material options

Option	Choices	Notes
M16 end	M16×2.0 (coarse) · M16×1.5 (fine)	Male or female
M12 end	M12×1.75 (coarse) · M12×1.5 · M12×1.25 (fine)	Sensor threads vary — tell us
Form	Adapter · reducing insert · double-male · female-female	To suit the job
Material	Steel · stainless 304 / 316 · brass on request	Plated or passivated
Seal	Plain · O-ring groove · sealing face	If it must be leak-tight
Drive	Hex · spanner flats · knurl for hand-tight	To suit clearance

Typical uses

• Sensor & probe mounts — fit an M12 sensor, transducer or thermocouple into an M16 boss, or the reverse.
• Instrument & fitting adaptation — gauges, valves and small fittings that don't share a thread.
• Thread repair — recover a stripped or oversized M16 hole with an M12 insert instead of scrapping the part.
• Light mechanical joints — eye fittings, standoffs and brackets where the two threads differ.

Other size adapters we machine

Where the M16 to M12 Catalogue Stops

If both ends are ×1.5 and you just need a plain reducer, buy it off the shelf — a stock gland reducer is cheaper than anything we can turn. These are the versions that are not on a shelf.

What you need	In the catalogue?	How we machine it
M16×1.5 female × M12×1.5 male, plain	Stocked	Both are standard gland threads. Buy it off the shelf; we would only quote it in 316 or a shortened body.
M16×2.0 × M12×1.25 — coarse one end, fine the other	No	Mixed pitch is the single most common reason this pair gets machined. Both ends single-point cut on one bar.
M16×2.0 × M12×1.75, both coarse	Rare	Stock reducers are built around gland pitches, not coarse ISO pitches. Turned to order.
Oversized M16 outside, M12 inside, to rescue a stripped M12 hole	No	A thread repair insert is not a catalogue reducer. We cut the outside to whatever the damaged hole cleans up to.
Double-male M16 × M12 stud	Thin	Male on both ends is a stud, not a bush, and stock lists carry far fewer. Any pitch pair.
Female M16 × female M12 coupling	Thin	Same reason — female-female across two sizes is rarely stocked.
O-ring groove or a flat sealing face on the M16 shoulder	No	Stock reducers seal on thread alone. We cut the groove to your cord size.
Reduced across-flats so the hex clears a neighbouring fitting	No	Catalogue hex sizes are fixed. State the clearance you have and we size the flats to it.
Left-hand thread on either end	No	Not a catalogue item at any size. Single-point cut like any other pitch.
316 stainless, or brass for a visible fitting	Rare below M20	Small stock reducers are usually zinc-plated steel. Material is open here — no tooling cost on a part this size.

Pitches above are the ones this page already lists; if your sensor or gland uses something else, state it and we cut that instead.

Frequently asked

Is this the same as an M16 to M12 cable gland reducer?

No. Gland reducers are thin brass or nylon with an O-ring, for cable entries. We machine a solid steel or stainless M16-to-M12 adapter for sensor mounts, mechanical joints and repair, in the exact pitch and form you need. Only need a gland reducer? A catalog part is cheaper.

Can you make it as a reducing insert to repair a hole?

Yes — M16 male outside, M12 female inside, to recover a worn M16 hole with a fresh M12 thread. We also do male-female, double-male and female-female.

Which pitches can you cut on an M16 to M12 adapter?

M16×2.0 or ×1.5, and M12×1.75, ×1.5 or ×1.25, plus non-standard pitches. Each end is gauged. More on coarse vs fine pitch →

Can I mount an M12 sensor in an M16 boss with this?

Yes — one of the most common uses. We machine an M16-male to M12-female adapter with a hex and, if needed, a seal face. Tell us the sensor thread and whether it must be leak-tight. See sensor adapters →

How much does an M16 to M12 adapter cost, and what is the minimum order?

Minimum order is 1 piece. A single M16 to M12 adapter turns in one setup with no tooling, so a one-off in brass or stainless stays affordable. Send both pitches and the seal requirement and you get a fixed price within 12 hours.