Helene Lesel taught us an ingenious way to check the width and depth of dadoes and rabbets, as well as a hole or notch on furniture you’re repairing or building. To measure the width, stand drill bits in the slot. When one ﬁts snugly, check the drill bit’s diameter for the exact width. To measure depth, lay bits lengthwise in the slot and hold a straightedge across the slot. When the straightedge lies ﬂat on the wood and just touches the bit, the bit’s diameter tells you the exact depth of the dado.