A 1940's Buescher 400 cornet had a broken screw on the water key, that was rusted-fast.
The repair went great. I used the Precision Screw Extractor set.
The Precision Screw Extractor worked perfectly. I needed to back out the screw without ruining the threads or marring the surface or denting any of the surrounding tubing. I soaked the broken screw in lubricant prior to extraction. The versatility of the extractor allowed me to work the screw from both sides until it was loose. The tool worked perfectly, and I love that it was made in the USA!