Thread prep
1/4-28 Tap Drill
Common shop chart tap drill for 1/4-28 UNF.
Last updated 2026-05-12Confidence: reference-derivedUNF
| Thread size | 1/4-28 |
|---|---|
| Tap drill | #3 |
| Decimal / mm | 0.213 in / 5.41 mm |
| Normal clearance | 0.266 in |
| Percent thread | 75% reference |
Thread prep
Common shop chart tap drill for 1/4-28 UNF.
| Thread size | 1/4-28 |
|---|---|
| Tap drill | #3 |
| Decimal / mm | 0.213 in / 5.41 mm |
| Normal clearance | 0.266 in |
| Percent thread | 75% reference |