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[Mike Sokol]

I've just finished an install of new speakers at a church and pulled down the old speakers, only to find that the brackets were lagged into the concrete block behind the plaster wall using tamper-proof breakaway screws. They're about 14 ft up on the wall with a lot of expensive statues and marble in the area. So do I drill these bolts out? Use a chisel and try to snap off the heads? Get an air powered saw like I used to use on exhaust pipes? Or is there something a little less messy with a lot less vibration, noise, dirt, etc...?

[Steven Barnes]

I would try to drill them out, if that did not work I would go with the grinder/cutoff disk to take the head of the bolt off. The second will be a bit messier, but still not too bad as long as you are only cutting the head off. Keep in mind you will probably have to grind the bolt flush after the bracket is removed unless they are not in a visible location.

The air chisel is usually a PITA to deal with the tool, compressor etc.

[Josh Millward]

Or you can use a dremel tool to cut a groove in the head and use a flat headed screwdriver tip on a driver to back it out.

Of course, success using this method will depend on the size of the bolts. Bolts that are smaller will be easier to deal with in this way, but large ones could be difficult to remove this way.

[Mike Sokol]

Hmmm....

Now I remember Easy-Out taps. Drill a hole in the center of the bolt, then the left-hand tap jams in the hole and lets you back it out. As long as the bolt isn't hardened this should work. It's been 40 years since I've done this but we used them on trucks all the time.

[frank kayser]

My vote would be a Dremmel with a cutoff wheel as my first effort as Josh suggested. Get the reinforced wheels - they break far less often.  I've removed many this way.  Be patient and make a good slot, not too deep as to give the bolt head a chance to break off. Just try to keep the slot sides square so you don't cam the things.
Freshly dress the screwdriver on the grinder before you set out.


Also, should you choose the dremmel, if you cut two slots at 90 degrees all the way to the bolt shank, the head will probably break off in quarters pretty easily.


Easy outs would be my third choice, but given the bolts are tamper proof, they just may be hardened.
Easy outs will take more time, too.  My luck with easy outs has not been all that positive.  I've broken more easy outs than I care to count.  They have to be made harder than the anticipated bolt, and though tempered, they are still quite brittle.


good luck, Mike!
frank

[Mark Cadwallader]

Mike, what is your purpose in removing the tamper-resistant bolts?  Do you need to re-use the threaded insert, or just clean up the old install by removing the existing brackets?  If the later, I would probably just use an abrasive cut-off wheel on a die grinder and cut them off flush with the wall.  There are electric die grinders (a Dremmel tool on steriods and meth) that are pretty robust. You will shoot a trail of sparks as you burn the steel away, but that shouldn't be too hard to contain with appropriate tarps/drop cloths. Wear appropriate PPE; eye and ear protection is a good thing.  (But you know that.)  Mark C.

Edit: Just snap the hex head off; less material to cut through that way. Once the hex is gone, you have what is basically a non-slotted truss head screw. Slot it or burn it away. Drag link sockets are a good way to get a wide, strong straight-bladed bit, btw.

[Mike Sokol]

Mike, what is your purpose in removing the tamper-resistant bolts?

I just need to remove the brackets, plaster the holes, then repaint. I don't need to reuse anything since the new speakers are already mounted in a totally different spot.

[Chad Graham]

Left handed drill bits will pull then out..

[Steve M Smith]

Get the reinforced wheels - they break far less often.

It's usually only once each!


The left hand tap option seems the best to me.  If you don't have the taps for it, a right hand tap with a machine screw and very tight locking nut could work.





Steve.

[John Roberts {JR}]

I've never used left handed drill bits but they sound like the perfect tool for this job.

Easy-outs are brittle. If you haven't broken an easy out, you haven't used them much.

JR

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