Inch series3 standards17 specification pages
1/4-20 Fasteners
All 1/4-20 screws, bolts, nuts and washers in the database. 1/4-20 has a nominal major diameter of 0.25 in, threaded 20 tpi to the UNC series, across 3 standards.
Nominal Ø0.25 in
Threads per inch20 tpi
Pitch Ø0.2177 in
Tap drill0.2000 in
1/4-20 thread dimensions
Full thread page- Designation
- 1/4-20 UNC
- Major diameter
- 0.25 in
- Threads per inch
- 20 tpi
- Pitch diameter
- 0.2177 in
- Minor diameter — external
- 0.1886 in
- Minor diameter — internal
- 0.1961 in
- Tap drill size
- Ø 0.2000 in
1/4-20 Bolts
8 pagesASME B18.2.1Hex Head Cap Screw — Inch Series
1/4-20 Screws
8 pagesASME B18.3Socket Head Cap Screw — Inch Series
1/4-20 Nuts
1 pagesASME B18.2.2Hex Nut — Inch Series