I run manual lathes and mills all the time at work.
1. What material are you cutting?
2. What diameter? Round stock, square stock, casting?
3. Tooling. Carbide or HSS?
4. 3 jaw or 4 jaw or collet or face plate?
Speeds and feeds are kind of important.
Feel free to PM me.
BTW this valve body is one of the best mods I have done, tranny is still doing just fine.