Acrylic & Chipboard For All Solid Kitchen Worktops Drainer Groove Jig (W)600mm (T)18mm. This Acrylic & chipboard drainer groove jig is suitable for the For all solid kitchen worktops. It measures by 600mm by 500mm & is used when you need to cut out a hole for an undermount sink in your kitchen worktop ideal for a perfect accurate cut out.