Titanium engine casing plug
This is a big beast. I had to screw cut an internal thread to use as an index for cutting the plug threads. its always a bit hit or miss doing it this way, but i usually get them within tollerence even if they aren’t quite as nice on the threads as i’d like. Notice this isn’t polished, the customer it is for doesn’t like them polished, he likes that ‘fresh from the machine’ look! good for him!