#6-32
- Threads per inch
- 32 TPI
- Nominal diameter
- 3.505 mm
- Series
- UNC
More dimensions
- Pitch
- 0.794 mm
VALICALC · TECHNICAL REFERENCE
UNC / UNF Thread Chart
Search a US thread designation to identify its diameter, series and threads per inch. Convert displayed dimensions without changing the thread's name.
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Search within the verified subset. Numeric sizes match complete designations; a nearby size is a candidate, not an exact match.
SELECTED REFERENCE
1/4-20
- Threads per inch
- 20 TPI
- Nominal diameter
- 6.35 mm
- Series
- UNC
All fields & cell provenance
- Pitch
- 1.27 mm
- Thread: Bolt Depot US thread pitch product reference — US Threads Per Inch Table: 1/4 · verified 2026-10-06 · source value 1/4-20.
- Threads per inch: Bolt Depot US thread pitch product reference — US Threads Per Inch Table: 1/4 · verified 2026-10-06 · source value 20.
- Nominal diameter: OSG Tap Drill Size chart — Tap nominal diameter / 1/4 · verified 2026-10-06 · source value 6.35.
- Series: Bolt Depot US thread pitch product reference — US Threads Per Inch Table: 1/4 · verified 2026-10-06 · source value UNC.
- Pitch: OSG Tap Drill Size chart — Derived25.4/TPI · verified 2026-10-06 · source value 1.27.
v1.1.0 · verified 2026-10-06
1/4-2020 TPIBack to answer ↑
Explore the verified data
16 matching rows · 16 in this subset
| Thread | Threads per inch | Nominal diameter | Series | Actions |
|---|---|---|---|---|
| #6-32 | 32 TPI | 3.505 mm | UNC | |
| #6-40 | 40 TPI | 3.505 mm | UNF | |
| #8-32 | 32 TPI | 4.166 mm | UNC | |
| #8-36 | 36 TPI | 4.166 mm | UNF | |
| #10-24 | 24 TPI | 4.826 mm | UNC | |
| #10-32 | 32 TPI | 4.826 mm | UNF | |
| 1/4-20 | 20 TPI | 6.35 mm | UNC | |
| 1/4-28 | 28 TPI | 6.35 mm | UNF | |
| 5/16-18 | 18 TPI | 7.938 mm | UNC | |
| 5/16-24 | 24 TPI | 7.938 mm | UNF | |
| 3/8-16 | 16 TPI | 9.525 mm | UNC | |
| 3/8-24 | 24 TPI | 9.525 mm | UNF | |
| 1/2-13 | 13 TPI | 12.7 mm | UNC | |
| 1/2-20 | 20 TPI | 12.7 mm | UNF | |
| 3/4-10 | 10 TPI | 19.05 mm | UNC | |
| 3/4-16 | 16 TPI | 19.05 mm | UNF |
#6-40
- Threads per inch
- 40 TPI
- Nominal diameter
- 3.505 mm
- Series
- UNF
More dimensions
- Pitch
- 0.635 mm
#8-32
- Threads per inch
- 32 TPI
- Nominal diameter
- 4.166 mm
- Series
- UNC
More dimensions
- Pitch
- 0.794 mm
#8-36
- Threads per inch
- 36 TPI
- Nominal diameter
- 4.166 mm
- Series
- UNF
More dimensions
- Pitch
- 0.706 mm
#10-24
- Threads per inch
- 24 TPI
- Nominal diameter
- 4.826 mm
- Series
- UNC
More dimensions
- Pitch
- 1.058 mm
#10-32
- Threads per inch
- 32 TPI
- Nominal diameter
- 4.826 mm
- Series
- UNF
More dimensions
- Pitch
- 0.794 mm
1/4-20
- Threads per inch
- 20 TPI
- Nominal diameter
- 6.35 mm
- Series
- UNC
More dimensions
- Pitch
- 1.27 mm
1/4-28
- Threads per inch
- 28 TPI
- Nominal diameter
- 6.35 mm
- Series
- UNF
More dimensions
- Pitch
- 0.907 mm
5/16-18
- Threads per inch
- 18 TPI
- Nominal diameter
- 7.938 mm
- Series
- UNC
More dimensions
- Pitch
- 1.411 mm
5/16-24
- Threads per inch
- 24 TPI
- Nominal diameter
- 7.938 mm
- Series
- UNF
More dimensions
- Pitch
- 1.058 mm
3/8-16
- Threads per inch
- 16 TPI
- Nominal diameter
- 9.525 mm
- Series
- UNC
More dimensions
- Pitch
- 1.588 mm
3/8-24
- Threads per inch
- 24 TPI
- Nominal diameter
- 9.525 mm
- Series
- UNF
More dimensions
- Pitch
- 1.058 mm
1/2-13
- Threads per inch
- 13 TPI
- Nominal diameter
- 12.7 mm
- Series
- UNC
More dimensions
- Pitch
- 1.954 mm
1/2-20
- Threads per inch
- 20 TPI
- Nominal diameter
- 12.7 mm
- Series
- UNF
More dimensions
- Pitch
- 1.27 mm
3/4-10
- Threads per inch
- 10 TPI
- Nominal diameter
- 19.05 mm
- Series
- UNC
More dimensions
- Pitch
- 2.54 mm
3/4-16
- Threads per inch
- 16 TPI
- Nominal diameter
- 19.05 mm
- Series
- UNF
More dimensions
- Pitch
- 1.588 mm
How to use this data
Nominal diameter and TPI identify the selected thread series. Metric pitch is 25.4 divided by TPI.
- Thread name and TPI remain inch-based when dimensional display is metric.
CHECK THE METHOD
Worked example
1/4-20 UNC has a 6.35 mm nominal diameter and 1.27 mm pitch.
Continue the reference workflow
Common lookup questions
Are 1/4-20 and 1/4-28 interchangeable?
No. The nominal diameter is the same, but thread pitch and series differ.
TRACEABLE DATA
Sources, scope & verification
Dataset v1.1.0
Last verified:
Eight common nominal sizes, UNC and UNF variants. Special/extra-fine pitches are outside this subset.
Values are curated product facts or generated scenarios. Paid standards, complete catalogs and source diagrams are not reproduced. A verification date applies to this documented subset.
Bolt Depot US thread pitch product reference ↗
Type C · BOLT · page version not stated
Selected dimensional product facts only; no catalog text, diagrams, standard tolerances or full paid-standard tables.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- bounded-product-facts
- Artifact SHA-256
- Public web page inspected; no retained source artifact hash.
OSG Tap Drill Size chart ↗
Type C · OSG · 800274CA-V3 / 2024
Selected dimensional product facts only; no catalog text, diagrams, standard tolerances or full paid-standard tables.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- bounded-product-facts
- Artifact SHA-256
- 20cf70a1a4b075ed05a818f08b16f1bed2161219258d8752e41d149489f05a51