This horizontal dial was the first dial I made for a latitude higher than 57° north where the sun rises before 3.00 am and sets after 9.00 pm (GMT) on midsummer day. With a dial plate 10mm thick and gnomon passing right though a slot in the plate it should survive for centuries.

A 5mm thick 'tenon' is held rigidly in place by passing through a close-fitting slot milled in the plate. Note the two holes by which stainless steel taper pins secure the gnomon firmly.

The taper pins are 'pocketed' in transverse slots 4mm deep to preserve a flush surface on the underside of the plate.