Collet ER25 Ø4 mm, FORTIS model TULEJKA ER25 FI 4 - 3 DIN6499

FORTIS TULEJKA ER25 FI 4 - 3 DIN6499 is an ER25 collet with a 4 mm inner diameter designed for secure clamping of round shank tools in milling spindles and collet chucks. Manufactured to DIN6499 dimensions, the collet ensures consistent clamping accuracy and concentric gripping, making it suitable for drilling, milling and finishing operations in both workshop and production environments.

Advantages

The ER25 design provides uniform radial clamping force across the tool shank, reducing runout and improving repeatability. Compliance with DIN6499 dimensions supports interchangeability with standard ER25 nut and holder systems. Its 4 mm bore is optimized for small-diameter end mills, drills and reamers, offering stable fixation during high-speed rotation and light to moderate cutting loads.

Suitable for

• Securing 4 mm round shank end mills and drills
• Milling, drilling and finishing tasks requiring concentric clamping
• Bench and production milling spindles using ER25 toolholding
• Tooling setups that require DIN6499-compatible components

Key specifications

• Collet type: ER25
• Inner diameter: 4 mm
• Standard: DIN6499 dimensions
• Material: spring steel (heat-treated for resilience)
• Clamping range: designed for precise 4 mm round shanks

How to use

Insert the tool shank into the collet bore and assemble the collet into an ER25 nut or chuck according to the machine manufacturer's instructions. Tighten the nut to the recommended torque so the collet compresses evenly around the 4 mm shank to achieve concentric clamping. Inspect the tool and collet for cleanliness and free of burrs before assembly to maintain accuracy and prevent damage.

Usage recommendations

For best performance, keep the collet and holder clean and free of chips and coolant residues. Use the correct ER25 nut and follow the machine's torque specifications. Replace the collet if signs of wear, deformation or significant loss of concentricity appear to maintain machining accuracy and safety.