When it comes to a lathe, bigger is always better. You can do small jobs in a large lathe but not vise versa. I consider my 14x40 lathe perfect for what I do but what is most important is the spindle bore through hole size to be able to pass material and barreled actions through. I've yet to find a job that I'm unable to perform on my mini mill though I wouldn't mind a larger one, but they're a nightmare to move.
Im guessing reason for the left hand threads on AK & SKS is similar to the reason why the propane & acetylene tanks have left hand threads so that its idiot proof. Maybe its because if the bullet is twisting left when its lefty loosy it will loosen the mussle device, doesnt the AR15 rifling twist counter clockwise thus is the 1/2x28?
