All spindle tapers deteriorate with use. The process occurs almost naturally.
SYMPTOMS OF A WORN SPINDLE:
CHECK FOR YOURSELF:
A quick inspection and test can confirm the need for requalifying your spindle. Visually inspect the spindle for chip marks in the taper. An abundance of small indentations usually means chips have caused a bell-mouth condition. Use a new tool holder to check the extent of the bell-mouth. Apply a small amount of HI SPOT Blue Dykem brand to the tool holder taper. Insert the tool holder into the spindle using the machine's retention system and allow to sit for approximately two minutes. Pull the holder and examine the taper. A light blue haze indicates good contact (the Dykem has been squeezed thin). Dark blue indicates areas of no contact. Read the wear on bluing as:
A GOOD RULE OF THUMB: IT TAKES 50% CONTACT OF THE AVAILABLE SURFACE OF THE TOOL HOLDER TO INSURE COAXIALITY, AND IT TAKES 90% CONTACT TO TRANSFER FULL LOAD HORSEPOWER.
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