Tool Study

J & M Machine has identified through testing that the pressure exerted by a standard retention knob after insertion into the toolholder does, in fact, expand and distort the toolholder shank. This distortion causes excessive vibration, short tool life, and reduced feed rates. Although the symptoms are universally recognized in the industry, the cause is not widely known.

Based on our thorough testing, we truly feel that by correcting the problem, the industry as a whole would see conservatively, a 10% savings in their milling costs.

We Would Like Your Help

We would like your help in educating not only the end-user CNC machinists, but also the machine manufacturers and their distributors, and the tooling distributors. We feel that the most effective way to reach this goal is to provide real numbers from real end-users.

To that end, we are requesting that you compare tool life before and after using the new High Torque Retention Knob and/or the Taper Shank Test Fixture.

Please leave a comment here, or e-mail us a copy of the results of your tool study at so we can post your results.

We appreciate your assistance in completing this tool study and in getting the message out to the industry.

Taper Shank Test Fixture & High Torque Retention Knobs
Contact us at to order your products.

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