width_step = (Range("max_w").Value - Range("min_w").Value) / 10
For read_row = 2 To calcline               ' for every optional set, do calculation
    If Worksheets("Calc").Cells(read_row, 1).Value = "" Then Exit For
    cur_width = Range("min_w").Value
    While (cur_width <= Range("max_w").Value)
    'For cur_width = Range("min_w").Value To Range("max_w").Value Step width_step    ' calculate for every width in 1mm steps
        Range("diameter_p").Value = Worksheets("Calc").Cells(read_row, 4).Value
        Range("diameter_g").Value = Worksheets("Calc").Cells(read_row, 5).Value
        Range("module").Value = Worksheets("Calc").Cells(read_row, 3).Value
        Range("width").Value = Round(cur_width, 1)
        Application.Calculate

        Worksheets("Result").Cells(write_row, 1).Value = Worksheets("Calc").Cells(read_row, 1).Value
        Worksheets("Result").Cells(write_row, 2).Value = Worksheets("Calc").Cells(read_row, 2).Value
        Worksheets("Result").Cells(write_row, 3).Value = Worksheets("Calc").Cells(read_row, 3).Value
        Worksheets("Result").Cells(write_row, 5).Value = Worksheets("Calc").Cells(read_row, 4).Value
        Worksheets("Result").Cells(write_row, 6).Value = Worksheets("Calc").Cells(read_row, 5).Value
        Worksheets("Result").Cells(write_row, 7).Value = Round(Range("sig_bend_p").Value * 100, 2)  ' take stress data from "Main"
        Worksheets("Result").Cells(write_row, 8).Value = Round(Range("sig_pit_p") * 100, 2)    ' and show as percentage
        Worksheets("Result").Cells(write_row, 9).Value = Round(Range("sig_bend_g") * 100, 2)
        Worksheets("Result").Cells(write_row, 10).Value = Round(Range("sig_pit_g") * 100, 2)
        Worksheets("Result").Cells(write_row, 11).Value = Round(Range("contact_ratio"), 2)   ' write contact ratio
        Worksheets("Result").Cells(write_row, 4).Value = Round(Range("width"), 2)   ' write width
        write_row = write_row + 1
        If ((cur_width + step) > max_w) Then cur_width = max_w Else cur_width = cur_width + step                    ' next width
    'Next cur_width
    Wend