Circular blanks of $$35$$ $$mm$$ diameter are punched from a steel sheet of $$2$$ $$mm$$ thickness. If the clearance per side between the punch and die is to be kept as $$40$$ microns, the sizes of punch and die should respectively be.

It is required to punch a hole of diameter $$10mm$$ on a sheet of thickness $$3mm.$$ The shear strength of the work material is $$420Mpa.$$ The required punch force is

A work piece of $$1000$$ $$mm$$ length and $$300$$ $$mm$$ width is machined by planning operation with a feed of $$0.3$$ $$mm/stroke.$$ The machine tool executes $$10$$ double strokes per minute. The planning time for a single pass is

A gear with $$84$$ teeth is to be machined using a milling process with indexing. The index plate has the following four hole circles: $$36,38, 42., 48.$$ The change gear ratio required is