Thread prep
1/4-20 Tap Drill
Common shop chart tap drill for 1/4-20 UNC.
Last updated 2026-05-12Confidence: reference-derivedUNC
| Thread size | 1/4-20 |
|---|---|
| Tap drill | #7 |
| Decimal / mm | 0.201 in / 5.105 mm |
| Normal clearance | 0.266 in |
| Percent thread | 75% reference |
Thread prep
Common shop chart tap drill for 1/4-20 UNC.
| Thread size | 1/4-20 |
|---|---|
| Tap drill | #7 |
| Decimal / mm | 0.201 in / 5.105 mm |
| Normal clearance | 0.266 in |
| Percent thread | 75% reference |