I am replacing my kitchen sink. The existing sink sits in a rectangular hole (with rounded corners) in the kitchen worktop. The worktop is about 1½" (40mm) thick and is made of some kind of particleboard (chipboard) with a laminate top surface.
The new sink is about ⅜" (10mm) wider and the same depth front to back. However it also has a smaller overhang.
Consequently I need to make the hole about ¾" (20mm) wider and about ⅜"(10mm) deeper. If I keep the sink centered that means cutting back ⅜"(10mm) and 3/16" (5mm) from each side.
This will have to be done with the worktop in place and from the top.
I don't have a suitable power tool (I have drills, sander, angle grinder, Dremel) so I'm wondering what to buy or hire.
From what I've read, the usual tool for this job is a jigsaw but I'm concerned that it will be difficult to cut such a thin slice around the hole using a jigsaw.
Should I buy a jigsaw or a router and what issues should I look out for?