Harry Bloom has stated several places he preferred CXA size toolpost . In part one his 4 part series in "Home Shop Machinist magazine" 2004-2005 where he details his complete rebuild of a 12CK he tells the story of buying the machine
"the seller closed the deal by tossing in an ALORIS BXA toolpost with several holders, which found a new home on my 10EE , an ALORIS CXA taking its place"
In one of his several PM posts where he mentions his CXA on 12CK he says that a CA size "is a tad too big" I have done probably several hours searching trying to find the actual top of the compound to lathe C/L .... I am not looking for recommendations as to what size toolpost to use on a 12CK.
That question has been answered many times on PM, everyone Harry Bloom , Johnoder and more agreeing on CXA . So far i have not found the actual measure , I would bet its on PM there , I am requesting a link to that info or someone who knows it please post.
And Thermite , thank you for drawing attention to proper nomenclature on the 12CK. A am putting it in my cell phone where it will remain close to my heart always ....LOL
David Lawrence