I have uploaded a program to the 'DOWNLOADS' section which calculates all possible thread pitches in metric and imperial for your CQ6230A-1 lathe such as the Chester UK 'Crusader' and many other Chinese made lathes
It calculates all possible combinations of change gears and gearbox settings for a lathe with METRIC FEED SCREW!
The program doubtless includes combinations for change gears you do not have and for combinations that for reasons of clearance etc would be impossible to mount on the machine.
The lathe that this program is for looks like this:
