undermount sink

Wonder if you guys can advise please. I’ve been installing a new kitchen and have solid oak worktops. When testing on some off cuts (new router, old one died) I noticed I’m getting some burn/ scorch marks. The router bits are new, is there a rule of thumb in minimising these scorch marks...

Currently fitting my new kitchen. As I like making things difficult for myself, I've decided to have an undermount sink and was wondering if anyone has any tips before I start. Have a 40mm oak worktop. I had intended to use a router with a top bearing bit and make up an mdf template. What's...