Spanish neck heel construction.....

Since this is a "Spanish Style" neck construction, the sides of the 'uke will be slotted in the neck. The difference between this style and the popular "glued on" or "bolted on" method, is that the heel is less bulky. Theorectially, the connection between the body and neck should be structually stronger then alternative methods. Historically, this is how classical guitars are built.

First, glue blocks together that will create the heel and slot joint for the 'uke sides.

When clamping the block together, to make sure they don't slide, they are placed along a fence and clamped  down to a flat surface.