Spindle liners can be used to fill the gap when barstock diameter is considerably smaller than a spindle. If the spindle ID is too large, excessive whipping and vibration of the bar can occur, resulting in potential damage to the spindle, marring of the barstock itself and overall poorer performance.
Available in steel, urethane and composite materials, spindle liners reduce the spindle ID to between 0.030 inch and 0.060 inch larger than the diameter of the bar being machined. The closer fit keeps the barstock on center in the spindle and allows faster machining speeds and closer machine tolerances.
Trusty-Cook Inc. offers a line of urethane spindle liners that originated about 35 years ago. The product has evolved to offer shaped ID—hex shapes, squares and rectangular work and extruded off-center jobs. Although steel liners are available for square and hex shapes, the pins placed in intermittent locations on either side to hold the liner’s shape can sometimes create issues. However, the urethane lines have the shapes molded, so feeding is as smooth with irregular shapes as with round stock.
To read more about spindle liners, visit “Line Your Spindles, Line Your Pockets.”
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