Drill Bits / U Diameter
Drill Bit Size for 7/16-14 Tap Is A U Drill Bit
A U drill bit is the standard tap drill size for cutting 7/16-14 UNC internal threads. When preparing a hole for a 7/16-14 tap, using the correct drill size is critical to achieving proper thread engagement, tap life, and dimensional accuracy.
Quick Drill & Tap Reference
- Thread: 7/16-14 UNC (coarce thread)
- Drill bit: Letter U
- Drill diameter: 0.3680 in
- Metric equivalent: 9.35 mm (approx.)
- Closest fractional size: There isn't a close fractional size that will achieve an acceptable thread fit without breaking the tap.
- Tap type: Hand tap or machine tap (material dependent)
Why This Drill Size Is Correct
For a 7/16-14 UNC thread, the recommended tap drill size is Letter U (0.3680 in). This diameter provides the proper percentage of thread engagement (75%) for general industrial use, balancing holding strength with manageable tapping torque. Using a U drill helps reduce tap breakage while maintaining accurate thread form in steel, aluminum, and common machinable alloys.
Typical Industrial Uses
A 7/16-14 tapped hole is commonly specified for structural assemblies, machine frames, tooling fixtures, and industrial equipment. Letter U drill bits are routinely used in CNC machining centers, drill presses, and manual milling operations where consistent tap preparation is required.
