The Alvord Polk 627-2 left hand spiral flute construction reamer is a Morse taper shank tool made of high-speed steel with no finish or coating, and is most commonly chosen for reaming interrupted cuts in structural steel. Construction reamers are tapered to allow the reamer to enter overlapping and misaligned holes where extremely precise tolerances are not necessary, and have a stop collar for safety and depth control.
Left-hand spiral reamers are useful for interrupted cuts and in through holes. Spiral reamers prevent whole flute contact with the leading edge in an interrupted cut, as in a keyway. This prevents damage to the interruption and reamer flute. Left-hand spiral style tools also push chips ahead of the tip of the tool, instead of pulling chips out of a hole. Left-hand spiral reamers are also useful when reaming through holes, since pushing chips into the hole can cause clogging, which may damage the tool. High-speed steel is a general purpose steel for cutting tools and is compatible with many metalworking materials. It is often lower in price than other cutting tool materials. Taper shank tools can be self-holding or self-releasing based on the degree of taper – small tapers are self-holding within the toolholder, while large tapers are self-releasing and will easily release from the toolholder. The end of Morse taper shank tools (held in a toolholder) is tapered to ensure accurate alignment of the tool in its socket and is self-holding (friction between the tool and the tool-holder prevents slippage). Morse taper is one of the most widely used standards for self-holding tapers.
For reamers in the 627-2 series with 0.3750 to 0.9375 inches diameter there are five flutes, and for 1.0000 to 1.5000 there are six flutes. Tolerances are +0.0030/+0.0060 inches for all reamers in the 627-2 series.
Reamers are used to finish existing holes. When holes are created using common applications like drilling or punching they often have minute imperfections. Their roundness may be flawed, or their diameter may be slightly smaller than required. Reamers are made to exacting tolerances, so they can correct such errors and create precisely round holes of exacting dimensions. Reaming is often used before tapping screw threads.
Alvord Polk manufactures a broad family of cutting tools, brushes, and tooling components, following ISO 9001 standards for quality and environmental impact of their products. Their offices and manufacturing facilities have been located in the United States since 1881.