#5-44 Tap Drill Size & Thread Specs
Everything for a #5-44 UNF thread on one page: tap drill (#37), clearance holes, wrench and hex key sizes, and the nearest metric thread.
SP-TD-01 · #5-44
#5-44 specs
SizePlate
#5-44 UNF · tap with
#37 drill
.1040″
2.64 mm · 71% thread
- Metric drill
- 2.65 mm · .1043
- Clearance
- #30 / #29
Thread
- Nominal size
- #5 · 3.17 mm
- Major diameter
- .1250″
- Threads per inch
- 44
- Pitch
- .0227″ · 0.577 mm
- Series
- UNF (fine)
- UNC version
- #5-40
Drilling
- Tap drill (75%)
- #37 · .1040
- Metric substitute
- 2.65 mm · .1043
- Tap drill (≈50%)
- #35 · .1100
- Close fit
- #30 · .1285
- Free fit
- #29 · .1360
Nearest metric
- Thread
- M3 × 0.5
- Major diameter
- 3 mm
- Pitch
- 0.5 mm
- Tap drill
- 2.5 mm
- Interchangeable
- No
Not interchangeable means the threads look close but won't run together: forcing one into the other strips both.
Drill size by thread percentage
Larger drill, less thread, easier tapping. 75% is the usual target.
| Drill | Decimal | mm | Thread |
|---|---|---|---|
| #38 | .1015 | 2.58 | 80% |
| 2.6 mm | .1024 | 2.6 | 77% |
| #37 | .1040 | 2.64 | 71% |
| 2.65 mm | .1043 | 2.65 | 70% |
| 2.7 mm | .1063 | 2.7 | 63% |
| #36 | .1065 | 2.71 | 63% |
| 7/64 | .1094 | 2.78 | 53% |
| #35 | .1100 | 2.79 | 51% |
| 2.8 mm | .1102 | 2.8 | 50% |
| #34 | .1110 | 2.82 | 47% |
Neighboring sizes
Questions
What does #5-44 mean?
A #5 nominal diameter with 44 threads per inch. It’s the fine (UNF) thread for that size; the coarse version is #5-40.
Can I use a 2.65 mm drill instead of #37?
Usually. 2.65 mm is .1043″ against .1040″ for #37, which changes the thread engagement by a few percent at most. The thread-percentage table above shows exactly how much thread each nearby drill leaves.