Not wanting to cut in line here guys so I hope an additional question is ok. I've been sort of shopping for another lathe as well. I currently have a Taig. I love it but she is pretty small. I looked at the specs on the G9972z and noticed the 8TPI on the lead screw. Is that exact or a close approximation? I was under the impression all of those had metric screws. That is one reason I have shied away from Asian lathes. Not that I'm being snobbish but I have a hard enough time getting it right as it is. I currently use lathe dials for the most part although sometimes I use a dial indicator.
Thanks in advance for your input
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You will hear vicious rumors like this on some of the "pro" forums, it is simply not true. Sometimes machinery salesmen will feed you this as a lie to sell you a machine, sometimes they actually believe it. You should be able to download the manual of any machine you are considering, the manual will tell you the truth.
If it says 8TPI it is 8TPI.
TBK, there is no machine with an "approximated" lead screw. Seriously, why would any factory tool up to make an approximate thread when they can just make a real thread. Chinese factories may be have all sorts of issues, but there is nothing wrong the Chinese engineer who designs the equipment.
The approximation part comes in when an imperial thread is cut from a metric lead screw. This entire approximation is handled by the change gears. When you buy a lathe with an imperial lead screw, it can be made to cut "approximate" metric threads the same way the metric machine cuts approximate imperial threads.
Pretty much all of these machines do have metric screws in the cross and compound, with an imperial dial added. You can spot these machines easily - the dial will register 0.040" per turn. The type of lead screw can be spotted by the number of teeth on the change gears, this is a separate topic. You should be able to find what gears go in an imperial or metric machine for cutting imperial threads and go from there. The gear ratios are pretty standard across all machines.
You can blame the French for this by the way. When the meter was arbitrarily set to 1/0,000,000 of the distance from the north pole to the equator measured through Paris, they lost any chance for convergence with the imperial system. The meter has basically gone down hill since then and is now some distance of how far light travels in some bizarre tiny fraction of a second and is still almost as arbitrary as before since the actual conditions for measurement only exist in a lab. Wouldn't it have been nice if the meter was 2 or 4 feet long and converting from metric to imperial was a simple matter of dividing by 2 or 10 depending on the direction of conversion?