What do the black marks indicate when using inletting black during stock inletting?

When using inletting black during stock inletting, the black marks represent high spots that need to be cut down. Inletting black, which is a form of marking compound, is applied to the surfaces being fitted together, such as the stock and the action of a firearm. After the components are pressed together, the marks left by the inletting black identify where there are raised areas on the stock that are making contact with the action. These high spots indicate where material needs to be removed to achieve a proper fit.

Identifying these high spots is crucial for achieving a secure and accurate mounting of the action within the stock, which ensures the overall functionality and aesthetic of the woodworking project. Adjustments can be made by carefully sanding or chiseling away the raised areas indicated by the black marks until a smooth, even fit is attained.