I believe those screws are an oddball size- - - - -maybe a 12-something? Measure the diameter and pitch of the thread, and check to see if there's a Heli-Coil available for it. If so, you might consider modifying all the threads. If they're 10-32, I'm pretty sure Heli-Coil makes that size thread insert.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!