To Drill or not to Drill?

[screenman]

When drilling make sure the entrance to the hole is slightly upwards not downwards. Many people get in the habit of allowing the drill itself to waiver away from the right angle it should be on tilted screens. On vertical screens keep the drill pointing down slightly. I hope this all makes sense even I cannot understand what I have written. In other word make the drill hole like a cup, which if turned even slight less than horizontal will not fill.