The Vortex 5C Metric Lathe Collet in Round Bore – 4mm is a soft, bore-ready 5C collet designed to be bored to your exact size, depth, taper, or shape. Used with a 5C lathe collet chuck, it gives you a customizable bore that matches your component with precision. It’s a versatile choice for engineers, machinists, hobbyists, and workshop environments that demand a precise, reliable fit on small parts. With a tight 13–15 micron runout, these collets deliver consistent bore accuracy across operations. Pins are used to keep the collet open during the boring process, making it straightforward to establish the bore and then re-bore later to accommodate larger parts. This means you can reuse the same collet for multiple jobs, reducing setup time and inventory while maintaining dependable performance. Bore-to-fit and re-bore for ongoing use: These soft 5C collets are designed to be bored to your exact size and can be re-bored multiple times to accommodate larger parts, extending tool life and lowering replacement costs. Low runout for consistent accuracy: A 13–15 micron runout ensures precise bore alignment, improving part concentricity and finish across turning and finishing operations. Pins provide controlled opening during boring: Dedicated pins keep the bore open during setup, ensuring clean entrances and repeatable bore diameters for reliable repeat jobs. This collet combination enhances your workflow by allowing rapid adaptation to different part sizes without swapping to new collets, delivering dependable grip, predictable results, and reduced downtime in busy shops or home workshops alike.