A better Case (was "Create Loop with Case statement")

In the code below I am having trouble creating a loop to check the contents of TextBox1 as it can have upwards of 8 characters. This case statement works fine as long as the character count is one.
How do I count how many characters are in Textbox1 and then loop thru them? Am I on the right thought track?

'Bunch of other code here (Similar to below except using other fonts)
            sTbItem1 = TextBox1.Value
            Select Case sTbItem1
                Case "."
                    sTbItem1 = Replace(sTbItem1, ".", "ù")
                Case "1"
                    sTbItem1 = Replace(sTbItem1, "1", "ï")
                Case "2"
                    sTbItem1 = Replace(sTbItem1, "2", "ð")
                Case "3"
                    sTbItem1 = Replace(sTbItem1, "3", "ñ")
                Case "4"
                    sTbItem1 = Replace(sTbItem1, "4", "ò")
                Case "5"
                    sTbItem1 = Replace(sTbItem1, "5", "ó")
                Case "6"
                    sTbItem1 = Replace(sTbItem1, "6", "ô")
                Case "7"
                    sTbItem1 = Replace(sTbItem1, "7", "õ")
                Case "8"
                    sTbItem1 = Replace(sTbItem1, "8", "ö")
                Case "9"
                    sTbItem1 = Replace(sTbItem1, "9", "÷")
                Case "0"
                    sTbItem1 = Replace(sTbItem1, "0", "î")
            End Select
        End If
    End If
    sTolerance = sTbItem1
    TextBox1.Text = sTbItem1
End If

Any hints, tips or examples are appreciated.