#5-44 UNF Thread
Recommended tap drill #37
Tap drill Ø 0.1040″ / 2.642 mm
Major Ø 0.1250″ / 3.175 mm
Threads per inch 44
The chart recommendation gives approximately 71.1% thread engagement — the conventional target for average materials. It is not the only valid choice; see the options below.
Specification
| Designation | #5-44 UNF |
|---|---|
| Thread family | Unified National Fine (UNF) |
| Nominal size | #5 |
| Basic major diameter | 0.1250″ / 3.175 mm |
| Threads per inch / pitch | 44 TPI (0.577 mm pitch) |
| Recommended tap drill | #37 (0.1040″ / 2.642 mm) |
Tap drill options by thread engagement
Any of these standard drills produces a usable engagement for #5-44 UNF; smaller drills give stronger threads but higher tapping torque. Percentages use the conventional approximation (60° thread form).
| Drill | Decimal in | mm | Approx. engagement |
|---|---|---|---|
| #38 | 0.1015 | 2.578 | 79.6% |
| 2.6 mm | 0.1024 | 2.6 | 76.7% |
| #37 — chart recommendation | 0.1040 | 2.642 | 71.1% |
| 2.7 mm | 0.1063 | 2.7 | 63.3% |
| #36 | 0.1065 | 2.705 | 62.7% |
Nearest drills to the tap drill in other systems
| Drill | Size | vs #37 | Resulting engagement |
|---|---|---|---|
| 2.6 mm | 0.1024″ / 2.6 mm | −0.042 mm | 76.7% |
| 7/64″ | 0.1094″ / 2.778 mm | +0.137 mm | 52.9% |
Clearance holes
For a bolt or screw of this size to pass through freely. Recommended drills per ASME B18.2.8: close, normal, and loose fits.
| Fit | Drill / Ø | Decimal in | mm |
|---|---|---|---|
| close | 9/64″ | 0.1406 | 3.572 |
| normal | 5/32″ | 0.1563 | 3.969 |
| loose | 11/64″ | 0.1719 | 4.366 |
Related threads
- #5-40 UNC — same nominal size, 40 TPI (Unified National Coarse (UNC)) · compare
- #4-48 UNF — next size down in UNF
- #6-40 UNF — next size up in UNF