So far I've learned that the controllers (NCs) on Okuma machine tools are windows based and that anyone can write programs that interface with the machine though what is known as the "THINC_API". Where can I find documentation on this API publicly available?
It should be installed along with the API. Look in the start menu under
Start | Programs | Okuma | THINC-API
The screenshot here is of a machining center but if you have a lathe, it should be in the same location too.