The Union Butterfield 940 uncoated high-speed steel square end mill has a multi-flute, non-center-cutting design and a 30-degree helix angle for general-purpose machining on a range of materials. The number of flutes varies; fewer flutes provide better chip-carrying capacity, while more flutes produce a finer finish. 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 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.