Every shop should have a Vee Block or two to hold round stock such as
dowels or metal tubing. They are handy for both drilling and cutting stock.

Alternate method of making a vee block.

Another method to make a vee block is to laminate strips together of increasing height and width. Start with one strip 1/8" wide, add a strip the same width on each side 1/8" higher. Then continue adding 1/4" wide strips, each one 1/4" higher than the last one. For additional strength drill holes for bolting it together at each end.