Import BDNA-20700 Straight Flute Tap 4-40 Unc Hss

Product Description

The IMPORT BDNA-20700 is a straight flute plug tap designed for cutting 4-40 UNC internal threads in a wide range of materials. Built from high-speed steel (HSS) and finished with a gold oxide coating, this tap offers improved lubricity and resistance to heat buildup during cutting operations. It features 3 flutes and a plug chamfer, which provides a gradual lead-in that works well for through holes and moderately deep blind holes. The overall length is 1-7/8 inches and the tap is ground to an H2 thread limit for consistent, close-tolerance threading. Right-hand thread direction is standard.

This tap is suited for light machine work, general metalworking, and maintenance or repair threading applications where 4-40 UNC fasteners are used. It is appropriate for use in manual tap handles, T-handle wrenches, or machine tapping setups. Typical materials include aluminum, mild steel, brass, and similar machinable metals. At 40 threads per inch on a No. 4 diameter, this is a fine-pitched thread commonly found in electronics enclosures, instrument panels, and small mechanical assemblies.

Key Features

• 4-40 UNC thread form, 40 threads per inch on a No. 4 major diameter
• Plug chamfer provides gradual thread engagement, suitable for through holes and moderate blind holes
• High-speed steel construction handles a broad range of machinable metals
• Gold oxide coating reduces friction and helps extend tool life
• H2 thread limit ensures close-tolerance thread production
• Right-hand thread direction, 3 flutes, 1-7/8 inches overall length

Compatibility

Designed as a standard replacement or general-use plug tap for any application requiring 4-40 UNC internal threads cut with a straight flute hand or machine tap.

Installation Notes

Threading operations should be performed by a qualified machinist or technician familiar with proper tap alignment and cutting technique. Always secure the workpiece firmly before tapping and use an appropriate cutting fluid for the material being threaded to prevent tap breakage. Back the tap out periodically to clear chips, especially in deeper holes. Inspect the tap for wear or chipping before each use, as a damaged tap can produce out-of-tolerance threads or seize in the workpiece.