Well... I found two errors to start with.

     private void NotifyPropertyChanged(String info)
        {
        if (PropertyChanged != null)
          {
          PropertyChanged(this, new PropertyChangedEventArgs(info));
          //CollectionChanged was null commented it off
          //CollectionChanged(this, new CollectionChangeEventArgs(CollectionChangeAction.Refresh, this.HoleList));
          }
        }

Second was that repaint screen was not getting called. You are binding to CurrentHolePattern so:

CurrentHolePattern.PropertyChanged += new PropertyChangedEventHandler(CurrentHolePattern_PropertyChanged);

This looks like it works:

    public Window1()
      {

      HolePatterns = new ObservableCollection<HolePattern>();
      HolePatterns.CollectionChanged += new NotifyCollectionChangedEventHandler(HolePatterns_CollectionChanged);

      CurrentHolePattern = new HolePattern();
      CurrentHolePattern.PatternName = "Test Pattern Name";

      //-- Set some default values for the UI
      CurrentHolePattern.BoltCirDia = 12.0;
      CurrentHolePattern.HoleCount = 6;
      CurrentHolePattern.StartAngle = 0;

      HolePatterns.Add(CurrentHolePattern);

      InitializeComponent();
      CurrentHolePattern.PropertyChanged += new PropertyChangedEventHandler(CurrentHolePattern_PropertyChanged);

      SketchX0 = canvas1.Width / 2;
      SketchY0 = canvas1.Height / 2;
      SketchBoltCirRad = canvas1.Width / 2 * .7;

      CoordinateGrid.ItemsSource = CurrentHolePattern.HoleList;

      RedrawScreen();
      }
 
    void CurrentHolePattern_PropertyChanged(object sender, PropertyChangedEventArgs e)
      {
      RedrawScreen();
      //RepaintScreen();  Repaint doesn't add new holes.
      }