For large datasets a faster solution is required.
Making use of 'Text to Columns' functionality provides a fast solution.
Example based on column F, starting range at 25 to LastRow
Sub ConvTxt2Nr()
Dim SelectR As Range
Dim sht As Worksheet
Dim LastRow As Long
Set sht = ThisWorkbook.Sheets("DumpDB")
LastRow = sht.Cells(sht.Rows.Count, "F").End(xlUp).Row
Set SelectR = ThisWorkbook.Sheets("DumpDB").Range("F25:F" & LastRow)
SelectR.TextToColumns Destination:=Range("F25"), DataType:=xlDelimited, _
TextQualifier:=xlDoubleQuote, ConsecutiveDelimiter:=False, Tab:=True, _
Semicolon:=False, Comma:=False, Space:=False, Other:=False, FieldInfo _
:=Array(1, 1), TrailingMinusNumbers:=True
End Sub