Hardwood treenails are generally made from selected black locust, and may vary in diameter as driven from 1¼ inches to 1½ inches, depending upon the thickness of the planking. All treenails, where possible, are driven through the ceiling inside, then cutoff flush on both ends and wedged with small oak wedges made for that purpose and called treenail wedges. The wedges must be set across the grain of the plank through which the treenail is driven. Where treenails are not driven through, a wedge is inserted in the end of the treenail which, when the treenail is driven, backs up against the bottom of the hole and wedges the treenail fast.

There are three general types of treenails in use. The first is straight, and is driven in a hole about 1/16 inch smaller than the treenail. When it is necessary to drive treenails of this type longer than 24 inches, it becomes rather difficult to get them in with the proper amount of drift. Hence, a second type has been devised where about one-half of the length of the treenail is sized about 1/8 inch smaller than the other half. These are driven in holes bored first about half-way through the hull with an auger 1/16 smaller than the large end of the treenail, and the rest of the way with an auger 1/16 smaller than the small part of the treenail. This in effect shortens the required length of drift and makes it possible to drive much longer treenails than would be the case with the first type. Such treenails are known as two drift treenails. The third type is tapered and driven in a two size hole bored in the same manner as described for two drift treenails. The large end of the treenail is about 1/8 inch larger than the larger portion of the hole, while the small end is the same size as the smaller portion of the hole. It is claimed that these treenails, when driven properly, cannot back out and that they actually hold the planking up against the frame.

All holes are bored, and all treenails are driven from the outside.

William Henry Curtis: The elements of Wood Ship construction ….
Philadelphia, (c1918). 23 cm, 31, 44, 45, 38, 62 pp, ill.
Published by the Education and Training Section, Industrial Relations Group, United States Shipping Board Emergency Fleet Corporation. Part I-II copyrighted 1918, by W.H. Curtis.

Transcribed by Lars Bruzelius

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