Reamer: An Essential Tool for Precision Machining


In the realm of metalworking and machining, precision is paramount. Achieving accurate and consistent results requires the use of specialized tools designed to create precise holes and shapes in various materials. Among these essential tools is the reamer, a cutting tool employed to enlarge or finish existing holes to a desired size and shape. This article delves into the world of reamers, exploring their types, applications, and the intricate process of reaming.

Definition and Function of a Reamer

A reamer is a multi-tooth cutting tool used to enlarge or finish holes in metal, plastic, or wood. Unlike drills, which create new holes, reamers are specifically designed to refine existing holes, ensuring precise dimensions and smooth surfaces. The cutting edges of a reamer are typically arranged in a helical pattern, allowing for efficient chip removal and preventing the tool from binding in the hole.

Types of Reamers

The world of reamers encompasses a diverse range of types, each tailored to specific applications and materials. Some of the most common types include:

  1. Hand Reamers: These reamers are manually operated and are commonly used in workshops and garages. They are available in various sizes and shapes, including straight, tapered, and spiral flutes.

  2. Machine Reamers: Designed for use in machine tools, machine reamers are typically more robust and can handle heavier workloads. They are often used in production environments where precision and consistency are crucial.

  3. Chucking Reamers: Chucking reamers are held in a chuck, a type of tool holder, and are commonly used in lathes and milling machines. They are versatile and can be used for a wide range of hole sizes and shapes.

  4. Shell Reamers: Shell reamers consist of a cylindrical body with multiple cutting edges. They are often used for finishing holes to precise tolerances and are particularly suitable for deep hole applications.

Applications of Reamers

Reaming finds applications in a multitude of industries, including:

  1. Automotive: Reamers are used to finish holes for bearings, bushings, and other components in engines, transmissions, and other automotive parts.

  2. Aerospace: The aerospace industry relies on reamers to create precise holes in aircraft components, ensuring structural integrity and performance.

  3. Medical: Reamers are employed in the production of medical devices, such as surgical instruments and implants, where precision and accuracy are of utmost importance.

  4. Electronics: Reaming is used in the manufacturing of electronic components, such as printed circuit boards (PCBs), to create holes for vias and other electrical connections.

The Process of Reaming

Reaming is a delicate process that requires careful attention to detail and proper technique. Here are the key steps involved in reaming:

  1. Hole Preparation: The first step is to prepare the hole by drilling it to a slightly smaller diameter than the desired final size. This ensures that the reamer has enough material to remove and create a precise hole.

  2. Reamer Selection: The appropriate reamer is selected based on the desired hole size, material, and application. Factors such as the number of flutes, cutting edge geometry, and material composition are considered.

  3. Reaming Technique: Reaming is typically performed using a slow and steady rotation of the reamer. Excessive force or speed can damage the reamer and result in poor hole quality.

  4. Lubrication: Lubricants, such as cutting oil or grease, are often used during reaming to reduce friction, improve chip removal, and extend the life of the reamer.

  5. Reamer Maintenance: Proper maintenance of reamers is crucial to ensure their longevity and performance. This includes regular cleaning, sharpening, and inspection for wear and damage.


Reaming is a fundamental process in metalworking and machining, enabling the creation of precise and accurate holes in various materials. With a wide range of reamer types and applications, this essential tool plays a vital role in industries such as automotive, aerospace, medical, and electronics. Understanding the types, applications, and process of reaming empowers machinists and engineers to achieve the desired results and maintain high standards of quality and precision in their work.