Hi and welcome to CoffeeSnobs
A KG100 isnt really up to espresso grinding (mine has long since been retired to plunger only use....) and it was modded prior to retirement.
The burrs arent fixed firmly in place and move.... and modding it makes these movements more of a problem - the burrs touch - hence the metal on metal noise.... they also produce lots of dust or very fine grinds.... wrecking your extractions.
Basically you need a real espresso grinder - these grinders are only suitable for machines with pressurised baskets- at best .... not real espresso machines.
A good grinder is FAR more important than the espresso machine when it comes to quality coffee... the minimum would be a EM480.... but they have reliability issues.... Id be looking at an Iberital or a Rocky to match your machine (as a minimum).