Reamers are precision cutting tools used primarily in the metalworking, woodworking, and plastic manufacturing industries. They are designed to enlarge existing holes to a precise diameter and create a smooth surface finish. The reamer described, with a diameter of 0.3125 inches (5/16 inch) and 0.3534 inches, measures 6-3/4 inches in length, making it suitable for a range of applications where accuracy and surface integrity are paramount. The historical development of reamers dates back to the late 18th century when they started to be used for finishing holes in metal after being drilled. They have continued to evolve in design and material composition, with modern reamers often made from high-speed steel or carbide, ensuring durability and sharpness for extended usage. This specific reamer is unbranded, which often indicates its use in a variety of settings where brand loyalty is not a defining factor. It is commonly used in both industrial applications and hobbyist projects. The dual diameter feature allows for versatility in hole enlargement processes, accommodating various size requirements within a single tool. Unique features include the precision ground flutes that provide efficient chip removal while maintaining cutting quality. The longer length of 6-3/4 inches allows for deeper reach into materials, making it advantageous in situations where standard shorter reamers may not suffice. Overall, this reamer represents a blend of historical craftsmanship and modern precision engineering, making it an essential tool in the arsenal of manufacturers and machinists alike.

Diameter: 0.3125 inches (approx. 5/16" diameter) Second Diameter: 0.3534 inches Length: 6-3/4 inches