CNC Collets

CNC collets are essential tool-holding devices designed to securely grip cutting tools—such as end mills, drills, and routers—in CNC machines. Whether you're operating a manual mill or a high-speed machining center, collets play a critical role in ensuring precision, stability, and reduced tool runout during operation.

Explore our full selection of ER collets, R8 collets, and SK/BT/HSK collet systems, all engineered for consistent performance across a wide range of machining applications.

Types of CNC Collets

ER Collets - Versatile, Self-Centering Tool Holders

ER collets are the most common collet type used in CNC milling and drilling. These slotted, conical sleeves fit into ER collet chucks and compress evenly around the tool shank when the nut is tightened.

Best for: General-purpose machining, round shank tools, end mills, and drill bits

Key Features of ER Collets:

• Self-centering design minimizes runout for improved accuracy
• Flexible clamping range with spring-style slits
• 8° taper provides consistent grip
• Ideal for CNC routers, milling machines, and drilling applications

R8 Collets - Direct Fit for Manual Milling Machines

R8 collets are commonly found on manual mills such as Bridgeport-style machines. They fit directly into the spindle and are secured with a drawbar, eliminating the need for a separate collet chuck.

Best for: Manual milling machines, general machining

Key Features of R8 Collets:

• 7/16"-20 drawbar thread for secure spindle engagement
• Holds tool shanks up to 3/4" diameter
• Precision ground for concentric tool holding
• Compatible with end mills, drill bits, and reamers

SK, BT, and HSK Collet Systems - High-Performance CNC Tool Holders

These industrial-grade collet systems are used in advanced CNC machining centers. Unlike standard collets, SK, BT, and HSK holders integrate both the spindle taper and tool holder, delivering exceptional rigidity, balance, and automation support.

SK Collets

Best for: European CNC machines, automatic tool changers

• German standard steep taper system
• Compatible with pull studs for ATC integration
• Metric threads for global compatibility
• Balanced and rigid for high-accuracy milling, drilling, and tapping

BT Collets

Best for: High-speed machining in automated environments

• Japanese symmetrical taper design (7:24)
• Balanced front-to-back for stable high-RPM operation
• Uses metric threads, similar to SK
• Popular in Asian and global CNC systems

HSK Collets

Best for: Ultra-high precision CNC machining and 5-axis systems

• Hollow shank with dual-contact taper and face interface
• Lightweight and short for rapid spindle speeds
• Expands at high RPM for superior grip
• Internal clamping system—no drawbar required
• Compatible with shrink-fit and hydraulic sleeves for extreme tool-holding force

Selecting the correct collet system is key to optimizing tool life, machining precision, and production efficiency. Whether you're running high-speed CNC routers or traditional vertical mills, we offer the tool-holding solutions you need to get the job done right.