Collet Maintenance

Poor collet maintenance is one of the most common causes of short tool life and tool breakage. A router bit can only perform well if the collet securing it is gripping the tool shank evenly and full length. A small amount of time spent regularly inspecting and cleaning the collet and tool holder will increase productivity, extend tool life and thereby reduce tooling costs. Following are critical components of the collet use:

• Internal Collet Surfaces.
  The most important surface is the inside of the collet. Resin often builds up on the inside of the collet, near the end, as it migrates there through the expansion slits on the collet exterior. This buildup prevents the collet from applying equal pressure points at the end of the collet, which, in turn, allows the tool shank to resonate inside, and slip in the collet. This slippage causes what is known as “collet burn”, a condition when resins are deposited on the shank of the tool in the form of brown or black markings. Resin buildup can easily be removed from the collet interior with a brass tube-type brush. These brushes are non-destructive, yet adequately remove the resins that solvents or air guns cannot.
• Internal Tool Holder Taper
  The inside taper of the tool holder is also a critical surface which also accumulates resin buildup and should be cleaned periodically!
• External Collet Taper
  The outside taper on the collet requires regular inspection and should be cleaned of all deposits and residues each time the tool is changed.
• Collet Change
  Collet maintenance includes replacing it every 500 machines hours. The small investment (+/- $30) will make a big difference in tool performance and preventing tool breakage which is usually a higher loss.
• Collet Nut
  The inside taper and threads of the collet nut must be cleaned and free of dust and burrs on the surface. If present, they will skew the collet and possibly ruin it. Lubricate the threads with a dry type lubricant for ease of assembly. For best tool performance, throw out any static nuts and replace them with ball bearing nuts!
  
  Below is a selection of cleaning tools available for ISO and HSK Tool Holders.