tailieunhanh - MAKING A TUSK TENON FOR KNOCKDOWN FURNITURE

The coasters serving as physical icons are depicted in Figure 9. The person holding the coaster, and only that person, has access to the information on the as- sociated exhibit. Each coaster is approximately inches in diameter, inches thick, and is made of a hollowed-outCorian base and a clear acrylic cap. An image of the associated exhibit is attached to the bottom of the cap, as shown in Figure 9. One component of the tagging system used to iden- tify the coasters and retrieve the associated data is a radio frequency identification device (RFID) tag em- bedded in the coaster. The tag, shown in the fore- ground of Figure 9,. | 1 Making a Tusk Tenon FOR Knockdown Furniture By Thomas Rettie In the Middle Ages like today people sometimes needed portable furniture. While we tend to think of medieval furniture as usually large massive and immobile there were many instances when furniture needed to be broken down and moved from place to place. In the home space was at a premium and bulky items such as tables were put up when not in use. In the workshop a table might be moved to where the light was best or taken to market for use as a counter. Even in death prized furniture might be sent with the deceased to the afterlife as with the Viking burial ship uncovered at Oseberg. A 16th Century German work table with tusk tenon joints after examples inJost Amman s Book of Trades . Copyright 2002 Thomas Rettie 2 The problem in making portable furniture is in devising joints that are strong when put together but that are easily taken apart and reassembled. Today we have a profusion of temporary metal and plastic fasteners but in a time when nuts and bolts had to be forged and cut by hand economical solutions were more limited. One solution is the tusk tenon. Also called a keyed tenon or wedged tenon the tusk tenon is a kind of mortise and tenon joint that uses a wedge-shaped key to hold the joint together. In a common mortise and tenon joint a protrusion on one part the tenon fits into a hole on the other part the mortise . Usually the joint is then locked with a peg using a technique called drawboring. In drawboring the holes for the peg are slightly offset so that the peg will pull the joint tighter when it is driven in. As the wood expands and contracts over time the peg can be driven further to keep the joint tight. The peg can also be driven out allowing the joint to be disassembled if necessary. With a tusk tenon a key is used instead of a peg to hold the joint together. Not only is the key easier to remove and replace it also provides added strength and stability to the joint. Because the key is

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