Abstract: A casting head and clamp arrangement for vacuum aspiration casting of metal rods in glass tubes is provided having a casting head with a generally vertical vacuum passage, a removable vacuum chuck in the lower end of said vacuum passage adapted to receive and hold the end of a glass tube, said chuck including a pair of spaced annular support discs, spaced elongate members connecting said support discs, sleeve members having an internal diameter larger than a glass tube to be held fixed on each of support disc annulus and projecting beyond said discs between the elongate members, an elastomer tube stretched and fixed at its opposite ends to the sleeve members and having an internal diameter smaller than the diameter of the glass tube to be held and vacuum means acting between said discs to cause the elastomer tube to enlarge in internal diameter under vacuum to permit insertion of the glass tubes to be held and to engage and hold the glass tube ends when the vacuum is released.