21. A flush rivet takes advantage of a countersink hole; they are also commonly referred to as countersunk rivets. 22. Predrill the holes at an angle and drive the nails, countersink them and fill the holes with wood filler. 23. The circle is shaped in a stamping press to create a downward countersink to fit snugly into the can body. 24. The result is the countersink of the end sits inside the top of the can body just below the flange. 25. If you countersink the screws, you can fill the holes with a wood plug, also adding to the design. 26. CAPTION : Countersink bit will bore the three different pilot holes needed for countersinking the head of a flat head screw. 27. Therefore, countersinks overlap in form, function, and sometimes name with chamfering endmills ( endmills with angled tips ). 28. Small ( c . 1 / 4 " diameter ) threaded drill bits and countersinks are common in aircraft metal work. 29. A magnetic core drilling machine fitted with a reversible motor can also be used for tapping, countersink and reaming operations. 30. Nail the sill with 3 1 / 2-to 4-inch galvanized finish nails, countersink and fill with putty.
