A treenail, also trenail, trennel, or trunnel, is a wooden peg, pin, or dowel used to fasten pieces of wood together, especially in timber frames, covered bridges, wooden shipbuilding and boat building. It is driven into a hole bored through two (or more) pieces of structural wood (mortise and tenon). History and general use The use of wood as a tenon can be traced back over 7,000 years, as archaeologist have found traces of wood nails in the excavation of early Germanic sites. Trenails are extremely economical and readily available, making them a common early building material. Black Locust is a favorite wood when making trunnels in shipbuilding in North America and English Oak in Europe due to their strength and rot resistance, while red oak is typical in buildings. Traditionally treenails and pegs were made by splitting bolts of wood with a froe and shaping them with a drawknife on a shaving horse. Treenails are cut from a single piece of wood and perform well because of the natural grain. The grain of the treenail runs perpendicular to the grain of the receiving mortises which adds structural strength. Treenails are typically in diameter and are hand whittled with rough facets. The mortise is drilled smaller than the treenail to create a tight fit and take advantage of friction in the mortise. In cases where the treenail is or longer, the treenail should be shaped smaller than the other half. In the same case the mortise is drilled in two parts, with a smaller auger for the smaller part of the treenail and a typical auger for the standard part. Other trenails are tapered with the large end being longer than the mortise. After treenails are hammered into the mortise, they can be trimmed, split, and wedged with a small piece of oak that increases friction force. As an alternative to the wedge, the treenail can receive a plug or a punch to the center that expands the entire circumference. While this method prevents leaks by reducing gaps, plugs and punches are more likely to fall out in cold temperatures. Ideally, the nose of the treenail is driven 4–5 cm clear of the timber before being trimmed. Unlike metal nails, trenails can not be removed (without great effort) or reused. As the wood shrinks or expand the fibers create a friction that interlocks it into the mortise snugly. If a