The Union Butterfield 943 uncoated high-speed steel double-end square end mill has four flutes, a 30-degree helix angle, and a non-center cutting, long-length design for applications that require a longer reach than standard-length end mills. Four flutes produce a better finish than fewer flutes. The long-length design has longer cutting edges than standard-length end mills for deep slotting and applications with a high depth of cut. High-speed steel is a common general-purpose steel for cutting tools and is compatible with a variety of materials. With no coating or surface treatment, this uncoated tool can be used on a broad range of materials. The double-end design has cutting edges on both end, allowing a new cutting surface to be substituted when the first shows wear, which doubles the tool’s life compared to single-end square end mills. The tool’s square end creates sharp, unrounded cuts. The 30-degree helix angle supports general-purpose applications. It balances lower angles’ strong cutting edge for difficult-to-machine materials with higher angles’ increased cutting action. The non-center-cutting design is for applications such as peripheral milling and finishing. The cutting diameter tolerance is +0.003” to -0.000”. This tool has a Weldon shank that provides a secure hold in the toolholder and helps prevent slippage. It meets ANSI specification B94.19 for quality assurance. End mills are designed to remove material and create multi-dimensional shapes and profiles. They have cutting edges along the outside diameter and flutes that remove chips from the cutting area and allow cooling fluids to enter. If heat is not reduced effectively, the tool’s cutting edges will dull and additional material buildup can occur. The number of flutes can range from two to eight. Two-flute designs offer the most efficient chip removal, but more flutes provide a smoother finish. The shank is the end of the tool held in place by a tool holder or machine. Center-cutting end mills can create three-dimensional shapes and profiles, and make plunge cuts similar to a drill bit. Non-center-cutting end mills are for applications such as peripheral milling and finishing, but cannot make plunge cuts. Precision Dormer manufactures cutting tools under the brands Precision Twist, Dormer, and Union Butterfield. The company has locations around the world, and makes tools that meet to ANSI, NAS, and DIN standards.