sheet1.Range['B2:C10'].Borders[xlEdgeLeft].Weight := xlThin;
sheet1.Range['B2:C10'].Borders[xlEdgeTop].Weight := xlThin;
sheet1.Range['B2:C10'].Borders[xlEdgeBottom].Weight := xlThin;
sheet1.Range['B2:C10'].Borders[xlEdgeRight].Weight := xlThin;
sheet1.Range['B2:C10'].Borders[xlInsideVertical].Weight := xlThin;
sheet1.Range['B2:C10'].Borders[xlInsideHorizontal].Weight := xlThin;