I find it interesting that while you never met your grandfather you know quite a lot about him. Neither I nor my mother remember what exactly my dad's job was called. I know that he did something with huge device/ computer. I know that device with some wire was cutting steal(or other metal?).I also know that his job was insanely precise- it had to be done right down to parts of millimetre/ hair(?) But I can't remember what the job was called...

Edit. I believe that this was made/cut by my dad at his job: