Axis.MinorGridlines (Word)

Returns the minor gridlines for the specified axis.

Only axes in the primary axis group can have gridlines.

With ActiveDocument.InlineShapes(1) 
 If .HasChart Then 
 With .Chart.Axes(xlValue) 
 If .HasMinorGridlines Then 
 ' Set the color to blue. 
 .MinorGridlines.Border.ColorIndex = 5 
 End If 
 End With 
 End If 
End With