This easy-to-use end mill holder screws onto the threaded end of the mill spindle. End mills are held in place with a single 10-32 set screw that tightens against the flat on the side of the cutter. This assures the end mill cannot spin in the holder during a heavy cut as is possible in a collet. An end mill holder also provides more support area for the end mill compared to a collet. A 3/32" hex key (not included) is used to tighten the 10-32 set screws. The 6081 1/8" end mill holder uses two 4-40 set screws. A 5/64" hex key is included with that holder.
Because of the ease of use of this type of cutter holder and the fact that it allows the use of longer or double-ended end mills, we have also made it available for other size cutting tools as well, but most American customers will find 3/8" tools to be available in the largest volume and variety and, therefore, the lowest prices.
In addition to end mills, special purpose cutters such as those designed for cutting key slots, dovetails and corner radii usually have 3/8" diameter shanks. The Sherline end mill holder will increase the versatility of your milling machine by enabling you to hold these popular cutters.
These holders also make a good "quick-change" tool system. By keeping your favorite cutters mounted in their own holders, changing cutters is a quick operation. Just unscrew one holder from the spindle and thread on another. In CNC operations, having several numbered holders pre-mounted with their own end mills means that each time a tool is changed, the tool length for any given tool remains unchanged. This means the tool diameter and length values in the tools table of your CNC program do not need to be updated.
Though this part may look simple, it is not easy to make. It must be made very accurately to be of any use. They are made on a CNC machine in a multi-step operation, with the threads being single-pointed rather than tapped to assure a high degree of concentricity. More details on how it is made are available in the instructions.