Ya logre hacerlo de todas formas gracios por tu ayuda ebolo.
Les pongo el codigo por si a alguien le interesa:
Public Function NumericOnly(KeyAscii As Integer, Optional extrachar As Variant) As Integer
On Error GoTo NumericOnlyErr
Select Case Chr$(KeyAscii)
Case "0" To "9", Chr$(vbKeyBack)
NumericOnly = KeyAscii
Case Else
NumericOnly = 0
If Not IsMissing(extrachar) Then
If InStr(extrachar, Chr$(KeyAscii)) Then
NumericOnly = KeyAscii
End If
End If
End Select
Exit Function
NumericOnlyErr:
NumericOnly = 0
Exit Function
End Function
Private Sub Text1_KeyPress(KeyAscii As Integer)
Select Case Index
Case 3
Case Else
KeyAscii = NumericOnly(KeyAscii)
End Select
End Sub