private void cmbShaftGrade_SelectedIndexChanged(object sender, EventArgs e)
 {
     double d = double.Parse(txtDf.Text);
     int shaftgrade = int.Parse(cmbShaftGrade.Text);
     InterferenceTolerance it = new InterferenceTolerance();
     txtShaftTolerance.Text = (it.getStandardOfTolerance(d, shaftgrade) / 1000).ToString("f4");
 }
 private void cmbFit_SelectedIndexChanged(object sender, EventArgs e)
 {
     double d = double.Parse(txtDf.Text);
     string str = cmbFit.Text;
     InterferenceTolerance it = new InterferenceTolerance();
     txtDeviation.Text = (it.getTolerance(d, str) / 1000).ToString("f4");
 }