M12×1.25 thread: 12 × 1.25 mm

Threads › M12×1.25

M12×1.25 is an ISO metric fine thread: 12 mm major diameter, 1.25 mm pitch, 60° form. Tap drill 10.8 mm. Clearance hole 13 mm (close) or 13.5 mm (normal).

Standard	ISO metric fine
Major diameter	12 mm
Pitch	1.25 mm
Thread angle	60°
Minor diameter, bolt	10.47 mm
Minor diameter, nut	10.65 mm
Tap drill	10.8 mm
Clearance hole	13 mm close, 13.5 mm normal
Usual class	6g bolt, 6H nut

Minor diameters worked out from the basic profile: major Ø − 1.22687 × pitch (bolt) and − 1.08253 × pitch (nut).

Open M12×1.25 in Benchsmith Add to order list

What the call-out means

`M`	ISO metric
`12`	Major diameter, mm
`× 1.25`	Pitch, mm. Given because it is a fine pitch
`-6g`	Bolt tolerance class (usual)
`-6H`	Nut tolerance class (usual)

Measure it

Bolt: Measure across the crests of the bolt with the caliper jaws. Worn bolts read 0.1 to 0.3 under.

Nut or tapped hole: Measure across the tops of the threads inside the nut or hole with the inside jaws. That is the minor Ø. Worn or oversize holes read a little over.

Same diameter, other pitch

M121.75 mm pitch
M12×1.51.5 mm pitch

Close in size, won't mate

Tr12×3Ø12 mm, 3 mm pitch
1/2-13 UNCØ12.7 mm, 13 TPI
1/2-20 UNFØ12.7 mm, 20 TPI
1/2 BSWØ12.7 mm, 12 TPI
1/2-10 ACMEØ12.7 mm, 10 TPI
7/16-14 UNCØ11.11 mm, 14 TPI

One size up or down

M10×1Ø10 mm (down)
M14×1.5Ø14 mm (up)

Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.