Busted Phillips Screws

There are also products called "Easy Outs" that are used to remove bolts whose heads have snapped off or been rounded. (They look like funky drill bits.) I don't know if these would work for your application, though. At hardware store or a good automotive supply store. Keep us posted if you use that Craftsman device. I'm sure that there are many others, besides myself, here on Agon who are curious if this "goober" really works! Keep you woofers a woofin'`and your tweeters a tweetin'!

Like Fatparrot said, they are called Easy Outs. First you have to drill a hole into the screw head so you can fit the easy out in there. The easy out is nothing more than a coarse, reverse threaded screw. They do work well if you know how to use them. If you are unfamiliar with them, I suggest you practice on a screw first, and then attempt the project at hand.

Be careful if you do decide to drill. The metal shavings may be attracted to the speaker magnet. If they get in around the voice coil you could have big trouble.

As a pro, drill it carefully with a drill slighty larger than the threaded part of the screw, you just want to take the heads off, do it to the rest of the stripped heads......... then you will be able to remove the plate, when you remove the plate the threads of the now drilled screws will be pertruding. use a vise grip to remove the screws. walla! damage free! get new screws and your done, and forget the power screw driver, when you install the new ones!

If the screws are countersunk then I think the best method is the one mentioned by Chichiuno. Most of the other methods involve some type of impact onto the speaker cabinet, which is not good. A high quality easy out still needs to be given a good tap in the drilled hole to set the edge in order to grip the damaged screw. If the cabinets are pretty sturdy this should be a minor concern.

All the above mentioned methods will work but drilling off the screw heads is the least stressful to the cabinet. If the screw heads are accessible, a pair of high quality diagonal cutters can grip the sides of the screw by actually digging into the sides & you can back them out while squeezing HARD.

If you're unable to drill I would take the approach which has the least amount of impact, so the first approach is the easiest. I would start with another screwdriver & if at all possible, lay the speaker face down so you can exert more pressure on the screwdriver. If you try this first use a high quality screwdriver & pay attention to the tip to screw line up.