A reamer is a rotary cutting tool with multiple cutting edges designed to accurately finish and enlarge pre-drilled holes. Its primary function is to refine the hole’s diameter and surface finish, ensuring it meets tight tolerance requirements. Reamers are not used to create holes from scratch. Instead, they remove a small amount of material from the inside of an existing hole to improve roundness, remove burrs, and achieve a precise final size.
Because of their ability to create consistently accurate and smooth holes with minimal surface roughness, reamers are used extensively in industries such as automotive, aerospace, and precision engineering, where proper fit and alignment are critical. This includes applications involving stainless steel, carbide materials, and high-precision components.
Reamers are used in a wide range of applications where hole accuracy is vital. Their main functions include:
Reamers follow a pre-drilled hole and gently enlarge it to the exact final diameter. They help remove irregularities left by the drilling process, such as uneven edges or slight out of roundness, improving dimensional accuracy.
A reamer provides extremely tight tolerances, producing holes that are round, straight, and smooth. This is essential for applications where one part must fit precisely into another, such as bearings, and housings, where shafts and pins are used for accurate location and fit. Whether using Shell Reamers, chucking reamers, or carbide reamers, the goal is always high-precision performance.
Reamers are also effective for removing burrs from hole edges. This enhances both the quality and safety of the finished component and reduces the need for further manual finishing during the grinding process or assembly.
Reamers operate through a rotary and linear motion. Here’s a breakdown of the reaming process:
Multi-Tooth Cutter
Reamers are manufactured with multiple cutting edges, at the edge of machined channels known as flutes, which can be straight or helical depending on the application. These flutes evenly distribute cutting force and improve chip control.
Rotation
During operation, the reamer rotates and moves linearly into the pre-drilled hole, guided by the existing bore. This keeps the tool aligned with the hole’s rotating axis.
Material Removal
Each cutting edge removes a very thin layer of material as the tool passes through the hole. This incremental cutting action results in a high-precision diameter and a refined surface finish, particularly important for a blind hole or tight-tolerance fit.
Different types of reamers are suited to different machining environments and tooling setups.
These are used with manual tools such as a T-handle or tap wrench. They typically have a square end to grip the wrench and feature a long taper at the cutting end to help guide the tool into the hole.
Machine reamers are designed to be used with equipment like drill presses, lathes, or CNC machines. They are often used in production settings where consistent, high-precision hole finishes are required.
Ideal for large-diameter holes and used with an arbor, shell reamers are a cost-effective solution for heavy-duty precision machining.
These reamers are commonly mounted in chucks and used in machines for repetitive high-accuracy operations, often requiring consistent drill size pairing and reduced reamer wear.
Made from solid carbide materials, these are used for the most demanding applications including hardened steels and abrasive composites, offering enhanced tool life and stability.
Reamers are typically manufactured from:
Advanced options may include coated reamers for enhanced performance in demanding environments, such as those involving stainless steel or titanium.
Reamers are essential in industries where precision holes are a standard requirement. Common applications include:
For aligning engine components, suspension parts, and transmission assemblies
For critical fastener holes in airframe structures, brackets, and components that require flawless surface quality
For jigs, fixtures, and precision tooling where components must align or rotate freely
At Exactaform, we supply high-performance reaming tools tailored to advanced manufacturing environments. Our offering includes:
We also offer tool refurbishment and retipping to extend tool life and improve long-term cost efficiency.
Looking to improve hole quality, accuracy, or surface quality in your production setup?
Our engineering team can help you choose or design the right reamer for your application.
Contact us today for technical advice, quotes, or support.