I recently purchased a huge old cnc milling machine. It is from circa 1980, and the person I bought it from did a retrofit on it to use LinuxCNC. But finding any documentation about this mill has been almost impossible.
Here is an album with pictures of my BTC-1: https://photos.app.goo.gl/gXBEVYJNcvcbrvvM7
However, someone who has two of these machines was kind enough to send me images of some documentation. I’ve posted it below in case someone else has one of these machines.
Here is another set of documents.