We don't have synonyms for puntil yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are until, pontil and puntel.
(n) :
Alternative form of punty. [(glassblowing) A metal rod used in the glassblowing process. After a glass vessel has been blown to approximate size and the bottom of the piece has been finalized, the rod, which is tipped with a wad of hot glass, is attached to the bottom of the vessel to hold it while the top is finalized. It often leaves an irregular or ring-shaped scar on the base when removed, called the pontil mark.]
(n) :
Alternative form of punty. [(glassblowing) A metal rod used in the glassblowing process. After a glass vessel has been blown to approximate size and the bottom of the piece has been finalized, the rod, which is tipped with a wad of hot glass, is attached to the bottom of the vessel to hold it while the top is finalized. It often leaves an irregular or ring-shaped scar on the base when removed, called the pontil mark.]