Disaster stuck while changing plugs on 320
Go to stanleyproto.com and look for a kit called DT-55, Screw extractor set.
They have a square profile with sort of a blade on each corner. I've used them for years and never had a failure yet. just tap them in a bit and twist. "you must have a bit of feeling, You will know when it's in far enough".
Easy peasy if the hole is already there, Gutted spark plug, hydraulic fitting etc..etc..



