The Union Butterfield 4535 uncoated high-speed steel right-hand spiral flute chucking reamer (also called a machine reamer) is a round shank tool with a 45-degree bevel lead, commonly used for general purpose reaming; it is also chosen for reaming interrupted cuts and blind holes (with only one opening). This tool is often used in a drill press, screw machine, or lathe. Right-hand spiral reamers are useful for interrupted cuts and blind holes (with only one opening). Spiral construction prevents whole-flute contact with the leading edge in an interrupted cut, as in a keyway. This reduces the possibility of damage to the interruption and to the reamer flute. Right-hand spiral tools pull chips away from the tip of the tool, instead of driving chips in front of the tool. As a result right-hand spiral reamers are useful when reaming blind holes, since pulling chips out of the hole prevents clogging as well as tool damage that can result from clogging.
High-speed steel (HSS) 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 and provide an economical alternative to coated tools. Round shank allows the reamer to be used with a variety of tool-holding systems. Like most non-tapered chucking reamers, this tool has a 45-degree bevel at the cutting tip that facilitates entry to pre-drilled holes.
In the Union Butterfield 4535 series, reamers 0.0625” to 0.1410” in diameter have four flutes, 0.1562” to 0.5312” in diameter have six flutes, and 0.5625” to 1.5000” in diameter have eight flutes. Tolerances for reamers up to 0.5000” are +0.0002” to -0.0000”; larger than 0.0500” and up to 0.7500” are +0.0003” to -0.0000”; and larger than 0.7500” up to 1.5000” are +0.0004” to -0.0000”. There is an exception for reamers that are dowel-pin sized; their tolerances are +0.0000” to -0.0002”.
Reamers are used to finish existing holes. When holes are created using common applications such as drilling or punching they often have minute imperfections. Their roundness may be flawed, or their diameters may be slightly smaller than required. Reamers are made to exacting tolerances so they can correct such errors and create precisely round holes with exact dimensions. Reaming is often used before tapping screw threads.
Precision manufactures machine tools under the following brands: Precision Twist, Precision Dormer, and Union Butterfield. They have locations around the world, and provide tools adhering to ANSI, NAS, and DIN standards.