Need Screw Size for Glow Plug Relay Ground Strap, Please!

[Sandra]

Greetings!
Could anyone kindly tell me the size of the two screws that secure the ground strap inside the box that contains not only it, but the relay as well? For example, like: 3/8"-17 (this would be 3/8", 17 threads per inch, I believe)
This is only an example to indicate the type of information I need. I'm stranded and in need of these screws to re-attach the ground strap and am right next door to a machine shop - if I can tell them the exact size, they can probably supply them to me. They are metric, no? Thank you in advance for any information any of you can supply!