Your customer sent you a metric part to make but you want to do it in inch. First you need to open an inch document and import the metric geometry. The drawing will be huge because 12.7 mm will be 12.7 inches but you can transform the geometry and curves just scale them by 1/25.4 (don't use .03937008), then make your features.
Or you can simply create the part with metric dimensions and use an inch postprocessor, FeatureCAM will do all the conversions for you and output the correct nc code in inch.

View list of all available tech tips