Tensioning keys, or adjustable wedge?

Aug. 25, 2006
Q: Do you have any experience with tensioning keys? They are designed to replace a die key by opposing wedges drawn together with a bolt. ...

... There is a demo offered by the current manufacturer at www.steelpol.com. We tried one of these years ago in our Impacter, but we thought we would never get it out, so we discarded the idea. Now I am considering this application in a drop hammer, but want to know if anyone has tried these with any success.

A: Yes, I am aware of the good and bad of the adjustable wedge or tensioning keys. For presses they work great-especially trim presses-for adjusting alignment between punches and trim blades.

For hammers, the jury is out because sticking is a problem. However, if you try one, be sure to lubricate the screws and wedge surfaces with powdered copper in grease, or use KopperKote from the makers of NeverSeize. This prevents sticking and galling, and might be worth trying if you are willing to do the maintenance.

For more than 40 years H. James Henning held key technical positions in the forging industry, including as director of technology for the Forging Industry Association, and as president of Henning Education Services, a Columbus, OH, firm specializing in customized education and training in forging technologies.

Guidelines and recommendations offered in this column are based on information believed to be reliable and are supplied in good faith but without guarantee. Operational conditions that exist in individual plants and facilities vary widely. Users of this information should adapt it, and always exercise independent discretion in establishing plant or facility operating practice.