A recent post to the Microsoft Excel Charting Newsgroup asked "how can I return a non-integer value from a scrollbar? A VBA approach would be to divide the scrollbar output by 10, 100, 1000, etc. Assuming the scrollbar is named "SB1", the example below returns values between 0.1 and -0.1:

Private Sub SB1_Change()
  Range("A1").Value = SB1.Value / 1000
  ScrollBar1.Max = 100
  ScrollBar1.Min = -100
End Sub

Private Sub SB1_Scroll()
  Range("A1").Value = SB1.Value / 1000
  ScrollBar1.Max = 100
  ScrollBar1.Min = -100
End Sub