This is a dead center hole locator for locating engine mounting holes. Great Planes Dead Center Hole Locater is a tool that should be in every modeler's toolbox. The tool is extremely easy to use. Simply press its self-centering alignment cone into the mounting hole with the engine positioned on the motor mount, and give the handle a few turns, the sharp drill tip leaves perfectly centered marks every time!
Length of tool: 6.75 to reach into cowls