Tap Drill Size Chart

M12 x 1.75 Tap Drill Size

Tap drill

10.2 mm 0.4016 in

Use a 10.2 mm drill (0.4016 in) for 79.2% thread.

Fine thread M12 x 1.5? Use 10.5 mm. (0.4134 in, 77.0% thread)

The drill size for a M12 x 1.75 tap is 10.2 mm (0.4016 in). If you are wondering what size drill bit a M12 x 1.75 tap needs, that is the one: it leaves 79.2% of thread, which is the figure standard tap and drill charts are built around. Below are the other holes you might want for this size - a larger drill for tough material, the form-tap hole, and the clearance holes for the bolt that goes in.

Every drill for M12 x 1.75

Tap drills and clearance drills for M12 x 1.75 (Metric coarse, 1.75 mm pitch). Percent of thread is the figure stored for each drill, which reproduces from the major diameter and pitch of M12 x 1.75.
Use Drill Decimal in mm % thread
Standard tap drill Cut tap, general use (D - P) 10.2 mm 0.4016 10.20 79.2%
Inch substitute Closest inch drill if you have no metric set Y 0.404 10.26 76.5%
Hard material Stainless, tool steel, anything that fights the tap 10.6 mm 0.4173 10.60 61.6%
Form (roll) tap Theoretical 11.23 mm - starting point, check your tap maker's chart 11.2 mm 0.4409 11.20 —

Clearance holes for a M12 x 1.75 bolt

A clearance hole is not tapped. It is the hole in the part the bolt passes through, so it is always larger than the thread.

Clearance holes for M12 x 1.75 per ISO 273. Clearance depends on the bolt diameter alone, so every M12 thread shares these figures.
Fit Hole mm Hole in
Fine 13.00 0.5118
Medium 13.50 0.5315
Coarse 14.50 0.5709

M12 x 1.75 dimensions

Nominal dimensions for M12 x 1.75. The basic internal minor diameter is the hole a 100% thread would start from, which is why no tap drill is ever that small.
Dimension Inch mm
Major diameter 0.4724 12.00
Basic internal minor diameter 0.3979 10.11
Pitch 0.0689 1.75
Thread designation M12 x 1.75

What the hole looks like

Cross-section of a M12 x 1.75 tapped hole, drawn to scale The drilled hole is 10.2 mm, 0.4016 inches or 10.20 millimetres across. The tap cuts outward from that wall to the major diameter of 0.4724 inches. A 100 percent thread would reach in to the basic minor diameter of 0.3979 inches, shown as a dashed line; the difference is why this drill gives 79.2% of thread. major 12 mm drill 10.2 mm · 10.2 mm dashed = 100% thread at 10.11 mm
M12 x 1.75 in section, to scale. The accent line is the thread the tap cuts from a 10.2 mm hole; the dashed line is where the crest would sit at 100% thread. The gap between them is the 20.8% of thread this drill leaves behind.

Work out a different hole for M12 x 1.75

Pre-filled with M12 x 1.75. Change the material, the tap type, or which drills you actually own, and it picks the closest real drill and tells you the percent of thread you end up with. The tables above are the published figures and do not depend on this.

The general-purpose target

Tap type
Drills you have

Best drill you have, cut tap, 70% target

10.4 mm0.4094 in70.4% thread

Theoretical hole 10.41 mm

One size down, deeper thread13/32″ 0.4062 in · 73.9%

One size up, easier tappingZ 0.413 in · 66.4%

For comparison, the published chart drill for M12 x 1.75 is 10.2 mm at 79.2% thread.

Notes on M12 x 1.75

Coarse pitch
M12 x 1.75 is the coarse pitch at 12 mm. It is the usual choice for general work, and it tolerates a slightly off-size hole better than the finer pitches do. Finer options at the same diameter: M12 x 1.5, M12 x 1.25, M12 x 1.
What the standard drill gives you
10.2 mm leaves 79.2% of thread (D - P). That is in the normal 65-80% band most shop charts aim for.
Stainless, tool steel and other tough material
10.6 mm opens the hole to 61.6% engagement. Less material for the tap to cut means less torque and less heat, at the cost of some thread depth.
Using a form (roll) tap
A form tap displaces metal instead of cutting it, so it needs a larger hole: 11.2 mm, against a theoretical 11.23 mm. Treat that as a starting point and check your tap maker's chart.
Closest inch size
1/2-13 is the nearest inch thread by diameter (12.7 mm against 12 mm). It is a planning reference only. The two are not interchangeable: the pitches differ, and a bolt from one will not run into a hole tapped for the other.

Related sizes

Same diameter, different pitch

Next size up and down

Closest inch size

1/2-13 27/64″ · 0.4219 in · 10.72 mm · 78.2% 12.7 mm major against 12 mm

Not interchangeable. 1/2-13 is the nearest size by diameter, nothing more. The pitches differ, so a 1/2-13 fastener will not run into a M12 x 1.75 hole and forcing one will strip both.

Guides for tapping M12 x 1.75

Longer reads on the decisions behind the numbers above.

All guides →

M12 x 1.75 tap drill: common questions

What size drill bit do I need for a M12 x 1.75 tap?
A 10.2 mm drill, 0.4016 in. That leaves 79.2% of thread, which is the standard chart figure for M12 x 1.75.
What is the drill size for a M12 x 1.75 tap in inches?
The 10.2 mm tap drill measures 0.4016 in. If you only have inch drills, Y (0.404 in) is the closest, giving 76.5% thread.
What drill should I use for M12 x 1.75 in stainless steel?
Use 10.6 mm instead of 10.2 mm. It leaves 61.6% of thread rather than 79.2%, so there is less material for the tap to cut and less chance of snapping it.
Is M12 x 1.75 the same as M12 x 1.5?
No. Both are 12 mm threads, but the pitch differs, so the drills differ: 10.2 mm for M12 x 1.75 and 10.5 mm for M12 x 1.5. The taps and the fasteners are not interchangeable.
What is the clearance hole for an M12 x 1.75 bolt?
For a medium fit, 13.5 mm per ISO 273. A clearance hole is not tapped; the bolt passes straight through it.
A 4 × 6 in card with the drills for this size.