Originally Posted by
handlewanker
Hi, I don't think high quality CNC commercial lathes of an industrial nature were the topic of the thread even if they do use the methods for CNC screw cutting you mentioned..
. I quite understand the process required with CNC turning and screw cutting.......not the using of it though, and the "leadscrew", that pushes the saddle along the bed, which for any CNC work would need to be a ball screw, and as it has a pitch is still a leadscrew even if it has balls instead of a solid nut with threads.
BTW......a leadscrew on a lathe is called that because it generates the pitch required to be cut as a division of it's own pitch when connected to the headstock spindle with a gear train.
What I proposed, and wanted to find out the problems arising, is to have a CNC lathe and direct couple the leadscrew and spindle with gears instead of an encoder etc .
You would then not have to change anything virtually in the spindle drive train, apart from converting the rest of the lathe from Acme threads to ball screws for the saddle and crosslide as would definitely be required to do CNC turning...etc etc.
This does not include having linear rails on the bed or crosslide, but can be a retrofit as with the removal of a compound rest there will be bags of room to fit linears as required.
It's not conventional in the CNC sense, but simple......where are the problems I asked.
Ian.