Note the the DDR, the devices are wider than the normal size. When we say Machine Doubling, it means that the machine altered the outside/inside edges of normal size devices, making them slight smaller. On a doubled die the devices are enlarged, wider/taller than normal. That is called spread. That is what to look for. A normal die/doubled die can be affected with Machine Doubling, but Machine Doubling doesn't make it a doubled die. Only a doubled die can strike a doubled die coin.