---
type: "thread"
name: "7/16\"-14 UNC"
designation: "7/16-14 UNC"
series: "unc"
series_name: "Unified Coarse (UNC)"
system: "unified"
size_label: "7/16"
tpi: 14
pitch_in: 0.071429
pitch_mm: 1.8143
basic_major_dia_in: 0.4375
basic_major_dia_mm: 11.1125
basic_pitch_dia_in: 0.3911
basic_pitch_dia_mm: 9.9339
basic_minor_dia_in: 0.3602
basic_minor_dia_mm: 9.1491
tap_drill: "U"
tap_drill_dia_in: 0.368
tap_drill_dia_mm: 9.3472
tap_drill_thread_pct: 74.9
clearance_normal_drill: "29/64"
tensile_stress_area_sqin: 0.106308
tensile_stress_area_sqmm: 68.586
internal_class_assumed: "2B"
standard: "ASME B1.1 (reference values based on the ASME B1.1 system; not a compliance claim)"
verified: "August 1, 2026"
url: https://shopmath.org/threads/unc/7-16-14
---

# 7/16"-14 UNC Thread — Dimensions, Tap Drill & Clearance

The tap drill for 7/16"-14 UNC is U — 0.3680 in (9.347 mm) — which leaves 74.9% thread engagement with a cut tap. Basic pitch diameter is 0.3911 in (9.934 mm) and basic minor diameter is 0.3602 in (9.149 mm). Tapped-hole figures on this page assume a class 2B thread; drill sizes for 50–85% engagement are in the tap drill table below.

- **Series**: Unified Coarse (UNC)
- **Designation**: 7/16-14 UNC
- **Threads per inch**: 14
- **Tap drill**: U
- **Standard**: ASME B1.1 (reference values based on the ASME B1.1 system; not a compliance claim)

## Basic Thread Dimensions for 7/16"-14 UNC

| Property | Inch | Millimetre |
| --- | --- | --- |
| Basic major diameter | 0.4375 | 11.113 |
| Threads per inch | 14 | — |
| Pitch | 0.0714 | 1.814 |
| Basic pitch diameter | 0.3911 | 9.934 |
| Basic minor diameter | 0.3602 | 9.149 |
| External thread root diameter | 0.3524 | 8.951 |
| Sharp V thread height (H) | 0.0619 | 1.572 |

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

## Tap Drill Sizes for 7/16"-14 UNC

Cut taps, from 50% to 85% thread engagement. The shop default is 75% — a U drill.

| Thread % | Target hole Ø (in) | Target hole Ø (mm) | Drill | Drill Ø (in) | Drill Ø (mm) | Actual thread % |
| --- | --- | --- | --- | --- | --- | --- |
| 50% | 0.3911 | 9.934 | 25/64 | 0.3906 | 9.922 | 50.5 |
| 60% | 0.3818 | 9.698 | W | 0.3860 | 9.804 | 55.5 |
| 65% | 0.3772 | 9.581 | V | 0.3770 | 9.576 | 65.2 |
| 70% | 0.3725 | 9.461 | 3/8 | 0.3750 | 9.525 | 67.4 |
| 75% (default) | 0.3679 | 9.345 | U | 0.3680 | 9.347 | 74.9 |
| 80% | 0.3633 | 9.228 | 23/64 | 0.3594 | 9.128 | 84.2 |
| 85% | 0.3586 | 9.108 | T | 0.3580 | 9.093 | 85.7 |

_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._

## Clearance Hole Sizes for 7/16"-14 UNC

The through-hole a 7/16"-14 UNC fastener passes freely, not the tapped hole.

| Fit | Drill | Hole Ø (in) | Hole Ø (mm) | Use |
| --- | --- | --- | --- | --- |
| Close | 7/16 | 0.4528 | 11.501 | Located joints, dowelled assemblies |
| Normal | 29/64 | 0.4685 | 11.900 | General assembly — the default |
| Loose | 15/32 | 0.4843 | 12.301 | Slotted or adjustable joints, weldments |

_Clearance holes per ISO 273 (metric) and ASME B18.2.8 (inch)._

## Thread Class Limits for 7/16"-14 UNC

Manufacturing limits for classes 2B, 3B, 2A, 3A. A gauge reading outside these bands is a reject, not a judgement call.

### External thread (bolt / screw) limits

| Limit | Class 2A (in) | Class 2A (mm) | Class 3A (in) | Class 3A (mm) |
| --- | --- | --- | --- | --- |
| Major Ø max | 0.4361 | 11.077 | 0.4375 | 11.113 |
| Major Ø min | 0.4258 | 10.815 | 0.4272 | 10.851 |
| Pitch Ø max | 0.3897 | 9.898 | 0.3911 | 9.934 |
| Pitch Ø min | 0.3850 | 9.779 | 0.3876 | 9.845 |
| Pitch Ø tolerance | 0.0047 | 0.119 | 0.0035 | 0.089 |
| Minor Ø max | 0.3433 | 8.720 | 0.3447 | 8.755 |
| Minor Ø min | 0.3386 | 8.600 | 0.3412 | 8.666 |
| Allowance | 0.0014 | 0.036 | 0.0000 | 0.000 |

### Internal thread (nut / tapped hole) limits

| Limit | Class 2B (in) | Class 2B (mm) | Class 3B (in) | Class 3B (mm) |
| --- | --- | --- | --- | --- |
| Major Ø max | 0.4539 | 11.529 | 0.4524 | 11.491 |
| Major Ø min | 0.4375 | 11.113 | 0.4375 | 11.113 |
| Pitch Ø max | 0.3972 | 10.089 | 0.3957 | 10.051 |
| Pitch Ø min | 0.3911 | 9.934 | 0.3911 | 9.934 |
| Pitch Ø tolerance | 0.0061 | 0.155 | 0.0046 | 0.117 |
| Minor Ø max | 0.3760 | 9.550 | 0.3717 | 9.441 |
| Minor Ø min | 0.3602 | 9.149 | 0.3602 | 9.149 |
| Allowance | 0.0000 | 0.000 | 0.0000 | 0.000 |

## Tensile Stress Area of 7/16"-14 UNC

| Property | in² | mm² |
| --- | --- | --- |
| Tensile stress area | 0.10631 | 68.59 |

The effective cross-section used to size a 7/16"-14 UNC fastener against a load. Multiply it by the material's allowable stress — the area itself carries no strength assumption.

## Other Thread Pitches in the Same Size as 7/16"-14 UNC

A 7/16 fastener is not always 7/16"-14 UNC. These are the other standard pitches cut on the same nominal size.

| Thread | Series | Pitch | Tap drill |
| --- | --- | --- | --- |
| [7/16"-28 UNEF](https://shopmath.org/threads/unef/7-16-28.md) | Unified Extra Fine (UNEF) | 28 TPI | Y |
| [7/16"-20 UNF](https://shopmath.org/threads/unf/7-16-20.md) | Unified Fine (UNF) | 20 TPI | 25/64 |

## Sources and Method for 7/16"-14 UNC

### Basic dimensions

- **Source**: NBS Handbook H28 (1969) Part I §§6-7 (public domain, 17 U.S.C. 105); normative modern reference ASME B1.1; series membership: Series membership: threadlib UIS_thread.csv (BSD-3-Clause); cross-checked against NBS H28 (1969) Part I Table 2.21; 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)
- **Method**: computed
- **Verified against**: NBS H28 (1969) Part I, Table 2.21 (public domain); cross-checked against FreeCAD CAM thread tables (LGPL-2.1+) — 1064 checks passed at 0.0001 in

### Tap drill sizes

- **Source**: 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
- **Method**: computed
- **Verified against**: Wikipedia Unified Thread Standard, preferred cutting tap drill size columns (CC BY-SA 4.0) — 36/39 published UNC+UNF rows reproduced

### Class limits

- **Source**: NBS Handbook H28 (1969) Part I §§6-7 (public domain, 17 U.S.C. 105); normative modern reference ASME B1.1
- **Method**: computed
- **Verified against**: NBS H28 (1969) Part I, Table 2.21 (public domain); cross-checked against FreeCAD CAM thread tables (LGPL-2.1+) — 1064 checks passed at 0.0001 in

### Formulas

**Tap drill hole diameter, inch threads**

```text
hole Ø  =  D − (%thread ÷ 100) × (1.29904 ÷ n)

  D = basic major diameter (in)
  n = threads per inch
```

_1.29904 = 2 × 0.64952, twice the engaged thread height per side on the 60° Unified profile._

**Actual thread engagement of the chosen drill**

```text
%thread  =  (D − drill Ø) × n ÷ 1.29904 × 100
```

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

**Tensile stress area, Unified inch threads**

```text
At  =  0.7854 × (D − 0.9743 ÷ n)²
```

_ASME B1.1 / NBS H28 form. Reproduces the stored value exactly for this thread._

### Assumptions

- The headline tap drill assumes 75% thread engagement, the general shop default. Every 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 2B internal thread, the general-purpose fit.
- Dataset scope: Le = 1D for UNC/UNF, 9P for UNEF — determined empirically against H28 Table 2.21, resolving data-sourcing.md open item 5. EXCLUDED: form (roll) tap drills, class 1A/1B limits, class 1AR allowances, constant-pitch UN series.

**Data last verified**: August 1, 2026

## Common Questions About 7/16"-14 UNC

### What is the tap drill size for 7/16"-14 UNC?

The tap drill for 7/16"-14 UNC is U — 0.3680 in (9.347 mm). That leaves 74.9% thread engagement with a cut tap.

### What is the pitch diameter of 7/16"-14 UNC?

The basic pitch diameter of 7/16"-14 UNC is 0.3911 in (9.934 mm). For a class 2B thread it runs 0.3911 in (9.934 mm) to 0.3972 in (10.089 mm).

### What is the minor diameter of 7/16"-14 UNC?

The basic minor diameter of 7/16"-14 UNC is 0.3602 in (9.149 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 7/16"-14 UNC?

7/16"-14 UNC has 14 threads per inch, a pitch of 0.0714 in (1.814 mm).

### What size clearance hole does a 7/16"-14 UNC fastener need?

close fit 7/16 (0.4528 in (11.501 mm)), normal fit 29/64 (0.4685 in (11.900 mm)), loose fit 15/32 (0.4843 in (12.301 mm)). The normal fit is the general-assembly default.

### What is the tensile stress area of 7/16"-14 UNC?

The tensile stress area of 7/16"-14 UNC is 0.10631 in² (68.59 mm²). Multiply it by the fastener material's allowable stress to get a load.

## Related pages

- Smaller in Unified Coarse (UNC): [3/8"-16 UNC](https://shopmath.org/threads/unc/3-8-16.md) — tap drill 5/16
- Larger in Unified Coarse (UNC): [1/2"-13 UNC](https://shopmath.org/threads/unc/1-2-13.md) — tap drill 27/64
- All Unified Coarse (UNC) sizes: [Unified Coarse (UNC) thread chart](https://shopmath.org/threads/unc.md)
- Every thread series: [Screw thread reference](https://shopmath.org/threads.md)
- Cross-series chart: [Tap drill chart](https://shopmath.org/charts/tap-drill.md)

---

*Source: [ShopMath](https://shopmath.org/threads/unc/7-16-14) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*