What is the tap drill size for M14×1.5?

The tap drill for M14×1.5 is 12.5 mm — 0.4921 in (12.500 mm). That leaves 77.0% thread engagement with a cut tap.

What is the pitch diameter of M14×1.5?

The basic pitch diameter of M14×1.5 is 0.5128 in (13.026 mm). For a class 6H thread it runs 0.5128 in (13.026 mm) to 0.5203 in (13.216 mm).

What is the minor diameter of M14×1.5?

The basic minor diameter of M14×1.5 is 0.4872 in (12.376 mm). That is the theoretical root of the internal thread, not the drilled hole size — see the tap drill table for the hole to drill.

What is the thread pitch of M14×1.5?

M14×1.5 has a pitch of 1.500 mm, the distance from one thread crest to the next.

What size clearance hole does a M14×1.5 fastener need?

close fit 15 mm (0.5906 in (15.000 mm)), normal fit 15.5 mm (0.6102 in (15.500 mm)), loose fit 16.5 mm (0.6496 in (16.500 mm)). The normal fit is the general-assembly default.

What is the tensile stress area of M14×1.5?

The tensile stress area of M14×1.5 is 0.19305 in² (124.55 mm²). Multiply it by the fastener material's allowable stress to get a load.

ISO Metric Fine · M14×1.5

M14×1.5 Thread — Dimensions, Tap Drill & Clearance

https://shopmath.org/threads/metric-fine/m14x1.5 · data verified August 1, 2026

The tap drill for M14×1.5 is 12.5 mm — 0.4921 in (12.500 mm) — which leaves 77.0% thread engagement with a cut tap. Basic pitch diameter is 0.5128 in (13.026 mm) and basic minor diameter is 0.4872 in (12.376 mm). Tapped-hole figures on this page assume a class 6H thread; drill sizes for 50–85% engagement are in the tap drill table below.

Series: ISO Metric Fine
Designation: M14×1.5
Pitch: 1.500 mm
Standard: ISO 68-1, ISO 261, ISO 262, ISO 965-1, ISO 898-1

Tap drill · 77.0% thread · cut tap

12.5 mm

Drill Ø: 0.4921in
Drill Ø: 12.500mm
Clearance (normal): 15.5 mm

Assumes 75% thread engagement with a cut tap and a class 6H hole. That drill actually leaves 77.0% thread.

Basic Thread Dimensions for M14×1.5

Basic thread dimensions — M14×1.5
Property	Inch	Millimetre
Basic major diameter	0.5512	14.000
Pitch	0.0591	1.500
Basic pitch diameter	0.5128	13.026
Basic minor diameter	0.4872	12.376
External thread root diameter	0.4787	12.160
Sharp V thread height (H)	0.0511	1.299

Basic dimensions are the theoretical values before any tolerance class is applied.

Tap Drill Sizes for M14×1.5

Cut taps, from 50% to 85% thread engagement. The shop default is 75% — a 12.5 mm drill. Deeper engagement means more holding strength and more torque on the tap.

Tap drill sizes by thread engagement — M14×1.5, cut tap
Property	Target hole Ø		Nearest standard drill			Property
Thread %	in	mm	Drill	in	mm	Actual thread %
50%	0.5128	13.026	13 mm	0.5118	13.000	51.3
60%	0.5052	12.831	12.8 mm	0.5039	12.800	61.6
65%	0.5013	12.733	12.7 mm	0.5000	12.700	66.7
70%	0.4975	12.636	12.6 mm	0.4961	12.600	71.8
75%default	0.4937	12.539	12.5 mm	0.4921	12.500	77.0
80%	0.4898	12.441	12.4 mm	0.4882	12.400	82.1
85%	0.4860	12.344	12.3 mm	0.4843	12.300	87.2

Target hole Ø is the theoretical hole for the stated engagement. The drill column is the nearest size in the standard number/letter/fractional/metric index, and actual thread % is what that real drill produces — the number that matters at the machine. Values are for cut taps. Tapped-hole figures assume a class 6H hole.

Clearance Hole Sizes for M14×1.5

The through-hole a M14×1.5 fastener passes freely, not the tapped hole.

Clearance hole sizes — M14×1.5
Property	Property	Hole Ø		Property
Fit	Drill	in	mm	Use
Close	15 mm	0.5906	15.000	Located joints, dowelled assemblies
Normal	15.5 mm	0.6102	15.500	General assembly — the default
Loose	16.5 mm	0.6496	16.500	Slotted or adjustable joints, weldments

Clearance holes per ISO 273 (metric) and ASME B18.2.8 (inch). The drill column is the nearest standard drill at or above the specified hole diameter.

Thread Class Limits for M14×1.5

Manufacturing limits for classes 6H. A gauge reading outside these bands is a reject, not a judgement call.

Internal thread (nut / tapped hole) limits — M14×1.5
Property	Class 6H
Limit	in	mm
Major Ø min	0.5512	14.000
Pitch Ø max	0.5203	13.216
Pitch Ø min	0.5128	13.026
Pitch Ø tolerance	—	0.190
Minor Ø max	0.4991	12.676
Minor Ø min	0.4872	12.376

Tensile Stress Area of M14×1.5

The effective cross-section used to size a M14×1.5 fastener against a load. Multiply it by the material's allowable stress — the area itself carries no strength assumption.

Tensile stress area — M14×1.5
Property	in²	mm²
Tensile stress area	0.19305	124.55

The formula this value comes from is in the sources section below.

Other Thread Pitches in the Same Size as M14×1.5

A M14 fastener is not always M14×1.5. These are the other standard pitches cut on the same nominal size.

Other standard pitches at nominal size M14
Thread	Series	Pitch	Tap drill
M14×2	ISO Metric Coarse	2.000 mm	12.1 mm

Sources and Method for M14×1.5

Basic dimensionscomputed+compiled

ISO 68-1 basic profile and ISO 898-1 tensile stress area; verified in docs/research/data-sourcing.md §3.2; diameter/pitch pairs: ISO 261 / ISO 262 diameter-pitch pairs via Wikipedia (CC BY-SA 4.0); cross-checked against threadlib metric_thread.csv (BSD-3) and FreeCAD CAM metric-internal-6H.csv (LGPL-2.1+); clearance holes: ISO 273 (metric) and ASME B18.2.8 (inch) via FreeCAD FeatureHole.cpp (LGPL-2.1+), cross-checked against bd_warehouse clearance_hole_sizes.csv (Apache-2.0)

Verified against threadlib metric_thread.csv (BSD-3-Clause) and FreeCAD CAM metric-internal-6H.csv (LGPL-2.1+), agreeing cell-for-cell — 215 checks passed at 0.001 mm

Part computed from the standard's formulas, part compiled from agreeing public sources.

Tap drill sizescomputed

Machinery's Handbook %-thread formula (geometry-derived); nearest-standard-drill-to-75% rule verified at 36/39 published chart rows in docs/research/data-sourcing.md §3.4

Verified against D-P rule verified as exactly the 77.0% thread case

Computed from the standard's formulas, then checked against published tables.

Class limitscompiled

threadlib metric_thread.csv (BSD-3-Clause) and FreeCAD CAM metric-internal-6H.csv (LGPL-2.1+), agreeing cell-for-cell

Verified against two independent published datasets agreeing cell-for-cell to 0.001 mm; ISO 965-1 formulas not located, so these are compiled not computed

Compiled from independent public sources that agree cell-for-cell.

Formula

Tap drill hole diameter, metric threads

hole Ø  =  D − (%thread ÷ 100) × 1.29904 × P

  D = basic major diameter (mm)
  P = pitch (mm)

1.29904 = 2 × 0.64952, twice the engaged thread height per side on the 60° ISO profile.

Actual thread engagement of the chosen drill

%thread  =  (D − drill Ø) ÷ (1.29904 × P) × 100

The drill column rounds to a real drill; this is the engagement that drill actually leaves.

Tensile stress area, ISO metric threads

As  =  (π ÷ 4) × ((d₂ + d₃) ÷ 2)²

  d₂ = basic pitch diameter
  d₃ = external thread root diameter

ISO 898-1 form, evaluated on unrounded intermediates — recomputing it from the rounded diameters shown above lands within 0.01%.

Assumptions

The headline tap drill assumes 75% thread engagement, the general shop default. Every other engagement from 50% to 85% is in the tap drill table — change the assumption and the number moves.
Tap drill figures are for cut taps. Drill diameters are nominal; a worn or run-out drill cuts oversize and reduces engagement further.
Tapped-hole figures assume a class 6H internal thread, the general-purpose fit.
Dataset scope: EXCLUDED: ISO 965-1 tolerance-grade formulas (not located — data-sourcing.md open item 2), 6g external limits (single-sourced), form tap drills, M68-M100 (verified demand cliff at M64).

Data last verified

August 1, 2026

How this data is built and checked →

How to Cite This M14×1.5 Reference

Citation

ShopMath. "M14×1.5 Thread — Dimensions, Tap Drill & Clearance." ShopMath, verified August 1, 2026, https://shopmath.org/threads/metric-fine/m14x1.5

BibTeX

@misc{shopmath-threads-metric-fine-m14x1-5,
  title        = {M14×1.5 Thread — Dimensions, Tap Drill & Clearance},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/threads/metric-fine/m14x1.5}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/threads/metric-fine/m14x1.5

Common Questions About M14×1.5

What is the tap drill size for M14×1.5?: The tap drill for M14×1.5 is 12.5 mm — 0.4921 in (12.500 mm). That leaves 77.0% thread engagement with a cut tap.
What is the pitch diameter of M14×1.5?: The basic pitch diameter of M14×1.5 is 0.5128 in (13.026 mm). For a class 6H thread it runs 0.5128 in (13.026 mm) to 0.5203 in (13.216 mm).
What is the minor diameter of M14×1.5?: The basic minor diameter of M14×1.5 is 0.4872 in (12.376 mm). That is the theoretical root of the internal thread, not the drilled hole size — see the tap drill table for the hole to drill.
What is the thread pitch of M14×1.5?: M14×1.5 has a pitch of 1.500 mm, the distance from one thread crest to the next.
What size clearance hole does a M14×1.5 fastener need?: close fit 15 mm (0.5906 in (15.000 mm)), normal fit 15.5 mm (0.6102 in (15.500 mm)), loose fit 16.5 mm (0.6496 in (16.500 mm)). The normal fit is the general-assembly default.
What is the tensile stress area of M14×1.5?: The tensile stress area of M14×1.5 is 0.19305 in² (124.55 mm²). Multiply it by the fastener material's allowable stress to get a load.

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