I have a spare 618 that I'm trying to piece back together. I purchased it as a basket case and it has lived up to that description. The spindle was "converted" to a dual thread. That means that someone threaded a 1"x8 tpi onto the 1"x10 tpi nose of the spindle. Now neither TPI will thread on all the way. I have a spare spindle from an Atlas horizontal mill that has the correct 1x10 nose.It looks like it may fit - has anyone ever done this? My only other option would be to machine away the current threads and press fit a collar which I would then thread. If you aren't familiar with the 618 lathes the early models had a 1x8 spindle thread and the later models had a 1x10.