Milwaukee Tool 49-57-5134 Straight Flute Tap 1/4-20 Unc

Product Description

The MILWAUKEE TOOL 49-57-5134 is a straight flute plug tap designed to cut 1/4-20 UNC right-hand internal threads in through-holes and open-bottomed blind holes. Manufactured from high-carbon steel with a black oxide finish, this tap provides corrosion resistance and reduced friction during the threading operation. It features a plug chamfer with 3 to 5 leading threads tapered to ease entry and distribute cutting load. With 3 flutes and a 2B class of fit, it produces threads compatible with standard 1/4-20 UNC fasteners. Overall length is 2.5 inches. Licensed machinists, maintenance technicians, and skilled tradespeople use this tap for general-purpose threading in mild steel, aluminum, and similar workpiece materials.

This tap is suited for production and maintenance threading applications where a 1/4-20 UNC thread form is required. The plug chamfer makes it the standard choice for through-hole tapping and for starting threads in blind holes where there is adequate clearance below the thread depth. It is commonly used in metalworking, HVAC bracket fabrication, electrical panel work, and general mechanical assembly. The black oxide coating helps resist rust during storage and reduces built-up edge during cutting. Thread pitch is 0.05 inches (20 threads per inch) and usable thread length is 1.0 inch.

Key Features

• 1/4-20 UNC right-hand thread form with 2B class of fit for standard fastener compatibility
• Plug chamfer with tapered lead threads for easy starting in through-holes and open blind holes
• High-carbon steel construction for cutting mild steel, aluminum, and similar materials
• Black oxide finish reduces corrosion and lowers cutting friction
• 3-flute design channels chips efficiently during hand or machine tapping
• No coolant-through requirement — compatible with cutting oil applied externally

Compatibility

Designed as a standard 1/4-20 UNC straight flute plug tap for use in any tap wrench, T-handle, or tapping head configured for the corresponding shank diameter. Suitable for through-hole and open blind-hole threading operations in soft to medium-hardness workpiece materials.

Installation Notes

Threading operations should be performed by a qualified machinist or skilled tradesperson familiar with proper tapping technique. Secure the workpiece fully before beginning and apply a suitable cutting fluid or tapping oil to extend tap life and improve thread finish. When hand tapping, reverse the tap one-quarter turn periodically to break chips and prevent binding. Do not force the tap if resistance increases sharply — back it out, clear chips, and re-lubricate before continuing.