Editing Treenail

{{short description|Wooden fastener}}
[[File:Sharpening_trenails.jpg|thumb|
Oak treenails that will be used to pin a wooden structure together. The one in the front has been used and pulled out, showing the way forces have permanently deformed the wood.

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A '''treenail''', also trenail, trennel, or trunnel, is a wooden peg, pin, or [[dowel]] used to fasten pieces of wood together, especially in [[timber frame]]s, [[covered bridge]]s, wooden [[shipbuilding]] and [[boat building]].<ref>Edwards, Jay Dearborn, and Nicolas Verton. ''A Creole lexicon architecture, landscape, people''. Baton Rouge: Louisiana State University Press, 2004. Print. 237.</ref>  It is driven into a hole bored through two (or more) pieces of structural wood ([[mortise and tenon]]).

==History and general use==
[[File:Holznägel, Fachwerk, Bandhaus Kloster Blaubeuren.jpg|thumb|Treenails used in timber framing of former cooperage and monastery cellar from 1478 at [[Blaubeuren Abbey]]]]
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.<ref>{{Cite book|title=Wood: A History|last=Radkau|first=Joachim|publisher=Polity|year=2012|isbn=978-0745646886}}</ref> Treenails are extremely economical and readily available, making them a common early building material.<ref name=":0" /> [[Black Locust|Black locust]] is a favorite wood when making treenails in shipbuilding in North America<ref>{{Cite book|title=Planking and Fastening|last=Specter|first=Peter|publisher=WoodenBoat Books|year=1996|isbn=9780937822418|pages=66}}</ref><ref>{{Cite book | url=https://books.google.com/books?id=qVUD70nM898C |title = Planking and Fastening|isbn = 9780937822418|last1 = Spectre|first1 = Peter H.|year = 1996| publisher=WoodenBoat Books }}</ref> and [[English Oak|English oak]] in Europe<ref>{{Cite book|title=Practical Treatise on the Joints Made and Used by Builders in the Construction of Various Kinds of Engineering and Architectural Works ...|last=Christy|first=Wyville|publisher=C. Lockwood and son|year=1904|pages=99}}</ref><ref>{{Cite web | url=https://books.google.com/books?id=5lcUAQAAMAAJ |title = Practical Treatise on the Joints Made and Used by Builders in the Construction of Various Kinds of Engineering and Architectural Works|last1 = Christy|first1 = Wyville J.|year = 1904}}</ref> 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]]. They can also be made with a tine-former, a hollow metal tube with a flaring flange on one end and a sharp edge on the other, usually mounted by the flange atop a low bench called a driving stool. Each roughly-shaped bolt of wood is placed above the sharp end of the pipe and hit with a wooden [[mallet]], but not hard enough that the mallet hits the sharp edge of the pipe; the next billet drives the preceding one the rest of the way through, and it falls through a hole in the bench into a bucket.

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 {{convert|1.25|-|1.5|in}} in diameter and are hand whittled with rough facets. The mortise is drilled {{convert|1/16|in}} smaller than the treenail to create a tight fit and take advantage of friction in the mortise. In cases where the treenail is {{convert|24|in|cm}} or longer, the treenail should be shaped {{convert|1/8|in}} 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 treenails are tapered with the large end being {{convert|1/8|in}} 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.<ref>{{Cite book|title=The Elements of Wood Ship Construction|url=https://archive.org/details/elementswoodshi00curtgoog|last=Curtis|first=W.H.|publisher=McGraw Hill Book Company|year=1919|location=New York, NY}}</ref> 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&nbsp;cm clear of the timber before being trimmed.<ref>{{Cite book|title=A Maritime Archaeology of Ships: Innovation and Social Change in Late Medieval and Early Modern Europe|last=Adams|first=J.R.|publisher=Oxbow Books|year=2013|isbn=978-1842172971}}</ref>

Unlike metal nails, treenails 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 treenail breaks or fails but the wood it is fastening remains intact the remaining treenail can be cut out and replaced with a larger treenail that fits snugly. In addition, treenails have the ability to move over time and retain structural integrity.

== Uses in building structures ==
[[File:TRUNNELS AND LOWER CHORD DETAILS. - Brown Bridge, Spanning Cold River, Upper Cold River Road, Shrewsbury, Rutland County, VT HAER VT-28-4.tif|thumb|Treenails used in the Brown Bridge in Rutland County, Vermont]]
Early mortise and tenon trusses with spans of less than {{Convert | 30 | ft | 0}} used treenail fasteners. When used in a truss, the connecting mortises are drilled off center such that when the treenail is inserted it creates a tighter joint. Because of the large number of treenails required in a truss, the treenails can be turned on a lathe with a head and a tapered end, often kept extra-long for the tightest fit. The bottom chord often requires 2–3 pegs and is the weakest part of the truss. Hence the treenail can not prevent failure in spans of over {{Convert | 30 | ft | 0}}. In cases where significant shrinkage may occur, it may be necessary to use iron U-straps or reinforcements.<ref>{{Cite journal|last=Nelson|first=Lee H.|date=1996|title=Early Wooden Truss Connections vs. Wood Shrinkage: From Mortise-and-Tenon Joints to Bolted Connections|jstor=1504495|journal=APT Bulletin|volume=27|issue=1/2|pages=11–23|doi=10.2307/1504495}}</ref>

== Uses in ships ==
{{See also|Lashed-lug boat|Sewn boat|Treenailed boat|Mtepe}}
[[Image:Trenails.jpg|thumb|Plank fixing, treenails and red lead paint, [[Qui Nhơn]], Vietnam]][[File:Building the Naga Pelangi - fitting the first plank.jpg|thumb|Building the [[Naga Pelangi]] - fitting the first plank required aligning many treenails]]Ancient shipbuilding used treenails to bind the boat together. They had the advantage of not giving rise to "nail-sickness", a term for decay accelerated and concentrated around metal fasteners. Increased water content causes wood to expand, so that treenails gripped the [[Plank (wood)|planks]] tighter as they absorbed water.<ref>Kettunen, P. O., ''Wood Structure and Properties''. Uetikon-Zuerich: Trans Tech Publications, 2006. 377. Print.</ref> However, when the treenail was a different wood species from the planking, it usually caused rot. Treenails and iron nails were most common until the 1780s when copper nails over copper sheathing became more popular.<ref name=":0">{{Cite journal|last=Johnson|first=W.|date=1986-01-01|title=Historical and present-day references concerning impact on wood|journal=International Journal of Impact Engineering|volume=4|issue=3|pages=161–174|doi=10.1016/0734-743X(86)90003-5}}</ref> As late as the 1870s, merchant ships used treenails and iron bolts, while higher quality ships used copper and [[Muntz metal|yellow metal]] bolts and dumps. In the 1870s, treenails were typically used in a ratio of four treenails to one bolt, although sometimes more bolts were used. In later corvettes, the ratio was changed to two treenails to one bolt.<ref>{{Cite book|url=https://archive.org/details/navalarchitectu00theagoog|page=[https://archive.org/details/navalarchitectu00theagoog/page/n236 232]|quote=wood architecture treenails.|title=Naval Architecture: A Treatise on Laying Off and Building Wood, Iron, and Composite Ships|last=Thearle|first=Samuel James Pope|date=1876|publisher=W. Collins, Sons & Company|language=en}}</ref>

== Uses in railroads ==
Similar wooden treenail fastenings were used as alternatives to metal [[Rail fastening system#Rail spikes|spikes]] to secure [[railroad]] rail-support [[Rail fastening system#Chairs|"chairs"]] to wooden sleepers ([[Railroad ties|ties]]) in early [[Victorian times]]. Treenails were extensively used constructing railways in North England.<ref>{{Cite book|url=https://books.google.com/books?id=8w-LRWovDb4C&q=wood+architecture+treenails&pg=PA236|title=The Civil engineer & [and] architect's journal|date=1841|publisher=Kent|language=en}}</ref>

==References==
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{{Woodworking}}

[[Category:Woodworking]]
[[Category:Shipbuilding]]
[[Category:Timber framing]]