Litespeed obed rear canti brake post size?


Retro Newbie
One of my rear canti brake posts snapped on my 1990s litespeed obed and going crazy trying to find replacement- the typical 10-8mm you find online look identical but thread is different- tried old cannondale and the diameter is too small. Of course litespeed was no help. Does anyone have any idea what size they are or where to get. Thanks