Collets & Collet Holders

Collet

This article gives a basic overview of the function and uses of collets, how to install them in collet holders, and finally their installation in the Haas CNC mill.

Overview

Collets

• A collet is a subtype of chuck that forms a collar around an object to be held and exerts a strong clamping force on the object when it is tightened.
• Reliable traits of collets include:
  • Fast chucking
  • Self centering
  • Strong clamping
  • Resistance against being jarred loose
  • Precise centering

Collet Blocks

• Collet blocks allow collets to be used in conjunction with machines, specifically lathes or in the vises used with mills. They are a larger hexagonal or square piece of metal, in which the collet is able to slide through and be fastened at the other end.

Square Collet Block

Hexagonal Collet Block

Square Collet Block in Vise

Hexagonal Collet Block in Drill Chuck

Types

R8

• R8 collets usually fit into the machine taper itself (i.e. there is no separate chuck). R8 was developed to allow rapid tool changes. R8 collets have a keyway to prevent rotation when fitting or removing. R8 collets are internally threaded.

5C

• 5C collets were developed primarily for work holding. 5C collets have an external thread at the rear for drawing the collet closed, and so work pieces may pass right through the collet and chuck.

R8 Collet

Inside R8 Collet

5C Collet

Collet Holders

Mounting Collet in Holder

Mill Installation

Step	Illustration
Choose appropriate collet size for tool being used
Select appropriate collet holder
*IMPORTANT* Snap the neck onto the collet as shown before placing into collet holder
Use appropriate tool to tighten neck onto collet holder
Final collet in neck and holder

Locations in Shop

• 5C collets can be found near the bottom of the cabinet across from Russ's office.
• R8 collets used in the manual mills can be found underneath the rolling tables next to the mills.
• R8 collets for use in the CNC mill can be found in the red cabinet near the CNC mill or under the rolling table next to the mill.

5C Collets Location

CNC Collet Sets

R8 Collets (under table next to mills)

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