Spindle Mounting
The shank is secured in a CNC collet or chuck.
Reamers / CNC hole-finishing tools
Machine Reamers
What Are Machine Reamers and How Do They Work?
Machine reamers are finishing tools built for rigid, automated setups. They remove a controlled amount of material from a pre-drilled hole to produce tight diametrical tolerances and a fine surface finish during CNC production.
Pilot Alignment
A chamfered tip guides the cutter into the existing hole.
Machine Cutting
Rotation and controlled feed allow the flutes to shear material from the bore.
Automated Evacuation
Selected flute geometry carries chips away during the cycle.
Key Features and Benefits of Machine Reamers
Solid Construction
Provides rigidity to help limit chatter in CNC machining centers.
Short Entry Chamfer
Supports rapid cutting engagement in production cycles.
Precision Flutes
Support fine surface finishes and close engineering tolerances.
Standardized Shanks
Provide secure mounting in industrial collets and holders.
Custom Profiles
Application-specific profiles can be engineered for specialized hole-finishing tasks.
Efficient Chip Clearing
Selected flute geometry helps reduce bore scoring and tool damage during continuous operation.
Machine Reamers Specifications
| Specification | Range / Details |
|---|---|
| Diameter Range | 1/16" to 2"; custom sizes up to 4" available |
| Flute Type | Straight, right-hand spiral, or left-hand spiral |
| Shank Type | Straight, Weldon, or Morse taper |
| Number of Flutes | 4 to 12, depending on tool diameter |
| Tolerance | Precision-ground to standard H7 or custom specifications |
| Format | Solid body or adjustable machine reamer |
Materials and Coatings Available for Machine Reamers
| Material / Coating | Best For | Key Advantage |
|---|---|---|
| Cobalt (HSS-Co) | High-volume production on tough alloys. | Offers greater heat resistance and edge life than standard HSS. |
| Solid Carbide | Abrasive materials and rigid CNC environments. | Provides high wear resistance and rigidity for close tolerances. |
| TiAlN Coating | Dry machining and high-temperature cutting. | Protects the substrate and can reduce friction. |
Cobalt HSS supports production in tough alloys, solid carbide provides rigidity and wear resistance in stable setups, and TiAlN can protect the substrate during dry or high-temperature cutting.
Which Machines Use Machine Reamers?
CNC Machining Centers
Use rigid holders for automated hole finishing.
CNC Turning Centers
Mount reamers in turrets to size internal diameters on rotating cylindrical parts.
Screw Machines
Integrate reaming into high-volume automated production cycles.
Applications and Industries for Machine Reamers
Engine-Block Bores
Sizes cylinder and valve-guide bores for automotive production.
Aerospace Fastener Holes
Finishes rivet holes to specified dimensional tolerances.
Hydraulic Cylinders
Reams fluid passages to support close-fitting seals.
Wear Compensation
Adjustable machine reamers can be expanded to compensate for gradual cutting-edge wear.
Bearing Housings
Machines interference-fit bores for bearings in rotating assemblies.
Frequently Asked Questions About Machine Reamers
What is the difference between machine reamers and hand reamers?
Hand reamers use square shanks and long entry tapers for slow manual turning. Machine reamers use round or tapered shanks for holder mounting and short lead chamfers for automated cutting.
When should I use adjustable machine reamers?
Use an adjustable machine reamer when controlled expansion is needed to compensate for wear and maintain diameter across a production run.
Why is selecting the right coating important in machine reaming?
Reaming friction generates heat. A compatible coating such as TiAlN can reduce friction and material buildup, improve the finished surface, and extend tool life.
Can a machine reamer correct a hole that was drilled off-center?
No. A reamer follows the existing pre-drilled path and will finish an off-center pilot hole off-center. The centerline must be corrected with a boring operation before reaming.
Does Bauron offer specialized flute geometries?
Bauron can engineer straight, left-hand spiral, or right-hand spiral flutes for the workpiece material, machine, and chip-evacuation requirements.
Shared engineering resource
Design and Engineering Support
Bauron provides design and engineering support for custom machine-reamer profiles, flute geometries, coatings, shanks, and tolerances. Share the material, machine capabilities, and chip-control requirements for technical review.
Talk to Engineering