BenchReference

M14 × 2 Thread

Recommended tap drill 12 mm
Tap drill Ø 0.4724″ / 12 mm
Major Ø 0.5512″ / 14 mm
Pitch 2 mm

The chart recommendation gives approximately 77% thread engagement — the conventional target for average materials. It is not the only valid choice; see the options below.

Specification

DesignationM14 × 2
Thread familyISO metric coarse
Nominal sizeM14
Basic major diameter 0.5512″ / 14 mm
Pitch2 mm
Recommended tap drill 12 mm (0.4724″ / 12 mm)
P = 2 mm 60° major Ø 14 mm 60° thread form (UN / ISO) — schematic

Tap drill options by thread engagement

Any of these standard drills produces a usable engagement for M14 × 2; smaller drills give stronger threads but higher tapping torque. Percentages use the conventional approximation (60° thread form).

11.8 mm 84.7% 12 mm ★ 77% 12.4 mm 61.6% shaded = share of the full thread height the tap forms · accent line = drilled hole wall
★ = chart recommendation. A smaller drill leaves more of the thread height for the tap to form.
Drill Decimal in mm Approx. engagement
11.8 mm 0.4646 11.8 84.7%
11.9 mm 0.4685 11.9 80.8%
15/32″ 0.4688 11.906 80.6%
12 mm — chart recommendation 0.4724 12 77%
12.1 mm 0.4764 12.1 73.1%
12.2 mm 0.4803 12.2 69.3%
12.3 mm 0.4843 12.3 65.4%
31/64″ 0.4844 12.303 65.3%
12.4 mm 0.4882 12.4 61.6%

Nearest drills to the tap drill in other systems

Drill Size vs 12 mm Resulting engagement
15/32″ 0.4688″ / 11.906 mm −0.094 mm 80.6%

Clearance holes

For a bolt or screw of this size to pass through freely. ISO 273 series (fine/medium/coarse), shown as close, normal, and loose.

Tapped hole Clearance hole 12 mm tap drill threads cut into the material 15.5 mm (normal fit) the tinted gap lets the bolt pass freely
Schematic — proportions exaggerated for clarity; use the table values.
Fit Drill / Ø Decimal in mm
close 15 mm 0.5906 15
normal 15.5 mm 0.6102 15.5
loose 16.5 mm 0.6496 16.5

Hex bolt & nut dimensions

For a standard hex bolt (ISO 4014/4017) and style-1 nut (ISO 4032) in this size.

Wrench / socket size (bolt head) 21 mm — legacy DIN: 22 mm
Head height 8.8 mm
Nut thickness 12.8 mm
Compatible nut M14 × 2 hex nut
Head — top view Bolt — side view Nut — side view width across flats = 21 mm wrench head height 8.8 mm thickness 12.8 mm

Basic (nominal) dimensions. See the wrench & socket size charts for all sizes and the metric ↔ SAE socket comparison.

Related threads

Data provenance. ISO 261 / ISO 724, ISO general purpose metric screw threads (ISO). ISO 2306, Drills for use prior to tapping screw threads (ISO). ISO 273, Clearance holes for bolts and screws (ISO). ISO 4014 / ISO 4017, Hexagon head bolts and screws (ISO). ISO 4032, Hexagon regular nuts, style 1 (ISO). Engagement percentages use the conventional approximation (engagement = (major − drill) ÷ (1.29904 × pitch)) and are guidance, not a tolerance specification. See all data sources.