T.J. Davies’ retention knobs are the highest quality retention knobs on the market. For over 50 years, we have been second to none. The retention knob or pull stud is a critical component to the tool holder’s performance and cutting tool life. We utilize 8620 and 9310 alloy steel for its high tensile strength to withstand strong centrifugal force, high load force, high feed rate, and difficult-to-machine material in the era of current CNC machining environment. As the forces exponentially increase, precision and strength in machining and tooling requires a higher quality of the retention knob or pull stud connecting the spindle to the tool holder.
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To maintain the tight tolerance of critical dimensions on a retention knob, we inspect our parts throughout the manufacturing process. We utilize batch production so that each retention knob has written inspection data and traceability to each batch. Additionally, the threads on our retention knobs are cut, which provides higher strength and excellent thread quality. Each retention knob is carburized to 58-62 RC. The finish on our retention knobs is 32 micro or better with a black oxide finish.