Try this code - 
Option Explicit

Sub consolidate_cols()
Dim i As Long, lcol As Long

Application.ScreenUpdating = False

With Worksheets("Input data")
    lcol = .Range("XFD1").End(xlToLeft).Column
    For i = 2 To lcol
        .Range(.Cells(1, i), .Cells(20, i)).Copy .Range("A" & .Rows.Count).End(xlUp).Offset(2, 0)
        .Range(.Cells(1, i), .Cells(20, i)).ClearContents
    Next i
End With

MsgBox "Copy paste complete."
Application.ScreenUpdating = True

End Sub
Copy the Excel VBA code
Select the workbook in which you want to store the Excel VBA code
Hold the Alt key, and press the F11 key, to open the Visual Basic Editor
Choose Insert | Module
Where the cursor is flashing, choose Edit | Paste

To run the Excel VBA code:
Choose View | Macros
Select a macro in the list, and click the Run button