Those look like 1/4 /20 thread. You can't use a full thread screw? Something like this:
https://www.homedepot.com/p/1-4-in-...ead-Machine-Screws-100-Pack-9005737/310394503
https://www.homedepot.com/p/1-4-in-...ead-Machine-Screws-100-Pack-9005737/310394503