What is the tap drill size for M16×1.5?

The tap drill for M16×1.5 is 14.5 mm — 0.5709 in (14.500 mm). That leaves 77.0% thread engagement with a cut tap.

What is the pitch diameter of M16×1.5?

The basic pitch diameter of M16×1.5 is 0.5916 in (15.026 mm). For a class 6H thread it runs 0.5916 in (15.026 mm) to 0.5991 in (15.216 mm).

What is the minor diameter of M16×1.5?

The basic minor diameter of M16×1.5 is 0.5660 in (14.376 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 M16×1.5?

M16×1.5 has a pitch of 1.500 mm, the distance from one thread crest to the next.

What size clearance hole does a M16×1.5 fastener need?

close fit 17 mm (0.6693 in (17.000 mm)), normal fit 17.5 mm (0.6890 in (17.500 mm)), loose fit 18.5 mm (0.7284 in (18.500 mm)). The normal fit is the general-assembly default.

What is the tensile stress area of M16×1.5?

The tensile stress area of M16×1.5 is 0.25923 in² (167.25 mm²). Multiply it by the fastener material's allowable stress to get a load.

ISO Metric Fine · M16×1.5

M16×1.5 Thread — Dimensions, Tap Drill & Clearance

https://shopmath.org/threads/metric-fine/m16x1.5 · data verified August 1, 2026

The tap drill for M16×1.5 is 14.5 mm — 0.5709 in (14.500 mm) — which leaves 77.0% thread engagement with a cut tap. Basic pitch diameter is 0.5916 in (15.026 mm) and basic minor diameter is 0.5660 in (14.376 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: M16×1.5
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

14.5 mm

Drill Ø: 0.5709in
Drill Ø: 14.500mm
Clearance (normal): 17.5 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 M16×1.5

Basic thread dimensions — M16×1.5
Property	Inch	Millimetre
Basic major diameter	0.6299	16.000
Pitch	0.0591	1.500
Basic pitch diameter	0.5916	15.026
Basic minor diameter	0.5660	14.376
External thread root diameter	0.5575	14.160
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 M16×1.5

Cut taps, from 50% to 85% thread engagement. The shop default is 75% — a 14.5 mm drill. Deeper engagement means more holding strength and more torque on the tap.

Tap drill sizes by thread engagement — M16×1.5, cut tap
Property	Target hole Ø		Nearest standard drill			Property
Thread %	in	mm	Drill	in	mm	Actual thread %
50%	0.5916	15.026	15 mm	0.5906	15.000	51.3
60%	0.5839	14.831	14.75 mm	0.5807	14.750	64.1
65%	0.5800	14.733	14.75 mm	0.5807	14.750	64.1
70%	0.5762	14.636	14.75 mm	0.5807	14.750	64.1
75%default	0.5724	14.539	14.5 mm	0.5709	14.500	77.0
80%	0.5685	14.441	14.5 mm	0.5709	14.500	77.0
85%	0.5647	14.344	14.25 mm	0.5610	14.250	89.8

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 M16×1.5

The through-hole a M16×1.5 fastener passes freely, not the tapped hole.

Clearance hole sizes — M16×1.5
Property	Property	Hole Ø		Property
Fit	Drill	in	mm	Use
Close	17 mm	0.6693	17.000	Located joints, dowelled assemblies
Normal	17.5 mm	0.6890	17.500	General assembly — the default
Loose	18.5 mm	0.7284	18.500	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 M16×1.5

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

Internal thread (nut / tapped hole) limits — M16×1.5
Property	Class 6H
Limit	in	mm
Major Ø min	0.6299	16.000
Pitch Ø max	0.5991	15.216
Pitch Ø min	0.5916	15.026
Pitch Ø tolerance	—	0.190
Minor Ø max	0.5778	14.676
Minor Ø min	0.5660	14.376

Tensile Stress Area of M16×1.5

The effective cross-section used to size a M16×1.5 fastener against a load. Multiply it by the material's allowable stress — the area itself carries no strength assumption.

Tensile stress area — M16×1.5
Property	in²	mm²
Tensile stress area	0.25923	167.25

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

Other Thread Pitches in the Same Size as M16×1.5

A M16 fastener is not always M16×1.5. These are the other standard pitches cut on the same nominal size.

Other standard pitches at nominal size M16
Thread	Series	Pitch	Tap drill
M16×2	ISO Metric Coarse	2.000 mm	14 mm

Sources and Method for M16×1.5

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 M16×1.5 Reference

Citation

ShopMath. "M16×1.5 Thread — Dimensions, Tap Drill & Clearance." ShopMath, verified August 1, 2026, https://shopmath.org/threads/metric-fine/m16x1.5

BibTeX

@misc{shopmath-threads-metric-fine-m16x1-5,
  title        = {M16×1.5 Thread — Dimensions, Tap Drill & Clearance},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/threads/metric-fine/m16x1.5}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/threads/metric-fine/m16x1.5

Common Questions About M16×1.5

What is the tap drill size for M16×1.5?: The tap drill for M16×1.5 is 14.5 mm — 0.5709 in (14.500 mm). That leaves 77.0% thread engagement with a cut tap.
What is the pitch diameter of M16×1.5?: The basic pitch diameter of M16×1.5 is 0.5916 in (15.026 mm). For a class 6H thread it runs 0.5916 in (15.026 mm) to 0.5991 in (15.216 mm).
What is the minor diameter of M16×1.5?: The basic minor diameter of M16×1.5 is 0.5660 in (14.376 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 M16×1.5?: M16×1.5 has a pitch of 1.500 mm, the distance from one thread crest to the next.
What size clearance hole does a M16×1.5 fastener need?: close fit 17 mm (0.6693 in (17.000 mm)), normal fit 17.5 mm (0.6890 in (17.500 mm)), loose fit 18.5 mm (0.7284 in (18.500 mm)). The normal fit is the general-assembly default.
What is the tensile stress area of M16×1.5?: The tensile stress area of M16×1.5 is 0.25923 in² (167.25 mm²). Multiply it by the fastener material's allowable stress to get a load.

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