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PDF icon“Great Beliefs and Misbeliefs” of Tolerance and Retention Knobs 
Article in CTMA VIEW – Winter 2010
Let’s review what we know about retention knobs and toolholders….New information was recently brought to light about V-flange tools and the relationship of the retention knob and the marks found on toolholders used in today’s CNC machining centers.

PDF iconThe Retention KnobArticle in NTMA RECORD – January 2010
Think back to the time before “NC” and “CNC” machines were introduced into the machine tool market.

PDF iconThe Knob Problem
Article in Modern Machine Shop – June 2009
The retention knob is an unmistakably critical component of the machining process. However, the tightening of the knob itself can lead to the toolholder not seating securely in the machine. You may be losing tool life to knob tightness without even knowing it.

PDF iconDo Your Toolholders Fit Your CNC Spindles? We’ve Taken A Second Look.
Article in CTMA View – Spring 2009.
Why is your toolholder showing finish wear at the threaded area and at the gauge line?

PDF iconCHART: Toolholder Taper Distortion Exceeding Grind
This chart (from CTMA article above) reveals the amount of distortion caused by tightening retention knobs.

PDF iconFitness Gage
Article in Cutting Tool Engineering – April 2009
An inexpensive gage for measuring a toolholder’s change in taper diameter

Retention Knob Comparisson Drawings

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