Wednesday, January 25, 2012

Building a Cherry TV Cabinet with Hand Tools - Part II

 

Starting the rip cut on the tail board. Begin the cut at the heel of the saw were the rip teeth are the smallest.


READ PART I of Building a Cherry TV Cabinet with Hand Tools


As with any woodworking process there are a host of ways to achieve similar ends. In this case the tails, pins and sockets were cut entirely with one small ryoba saw and a few nomi. I considered using a router with a straight cutter to clean out the bulk of the tail sockets but decided to stick with hand tools and chop this material away in a more traditional manner. For layout tools I used a marking gauge called a kibiki, left and right marking knives (???), small square, mechanical pencil and a wooden dovetail template. 


The design and layout of dovetails is open for expansive variation and creativity. Typically a narrow pin is considered more refined. I decided on seven evenly spaced and relatively narrow pins with six moderately large tails per joint. The dovetails are cut at an 8° pitch. I begin by laying out the tails on the outside face of the side panels, with the plan to cut right to my line. The tails are marked in pencil with the dovetail template and squared across the end. The completed tail board will be used as a template for marking the pins and tail sockets. Therefore any variation in layout or cutting will be carried forward and ultimately lost in the mix.


I sawed the tails using the rip cutting edge of a Mitsukawa - 195 mm super deluxe ryoba. This is a fairly small saw that as is typical of Japanese saws also has finer teeth. I sawed to the center of my pencil line removing the half of the line on the waste side of the cut. While cutting, my aim is to cut straight, cleanly and square. I worry less about slight variations on the pitch angle of the tail. 


Once the sides of the tails are sawn I score the bottom of the pin sockets with the kibiki marking gauge and chop the waste away. I typically chop from both faces leaving 1/32" to 1/16" for clean up depending how the material is cutting. I alternate chopping down from one face and then chip out 1/16" or so of material from the end. I tend to cut about 1/3rd of the way through from the inside face and then take the remainder from the outside face. Once the bulk of the material is cleared I pare the bottom of the socket clean making sure that it is square from the outside to the inside. With a chisel, square and straighten the sides of any tails that require it. The tail board is now ready for transferring the layout to the pin board.


I clamped the sides to the top one at a time using a simple plywood 90° corner jig so that I could transfer the layout. I marked as much as possible with marking knives and also traced the layout in pencil. After unclamping the top I scored the thickness of my side panels with a kibiki to the inside face of my top panel. Then I squared the layout of the pins around to that line with a marking knife. I like to locate my square by first inserting the marking knife into the end of the previous layout mark and then slide the square up to the knife. 


I saw as close to my marks as I dare, usually leaving just enough waste to clean up later with one or two passes of a chisel. Chopping out the waste on the tail sockets is pretty much like removing the waste on the pin sockets except that with half blind dovetails all the work is done from the inside face of the panel. Once again I chop down staying just to the waste side of the layout and chipping out the material from the end.


Chopping Out the Tail SocketsSet the chisel for your fist cut so that the wedging action of the chisel leaves the back of the tool about 1/32-in. back from your scribed shoulder line.

Alternate chipping out the waist on the tail sockets.


Clean up the final 1/32-in. on the depth of the tail sockets.



Once all the tails and pins have been cut clean to the layout lines I chisel a small chamfer on the inside faces of the tails where they won't show when the joint is completed. Then I test fit the joint looking carefully and feeling for tight fitting areas. Burnished or scratch marks can be clues to where the joint needs to be eased. With hard or brittle woods I like to be able to easily tap a joint like this at least three quarters of the way home. Softwoods that compress well can be test seated less deeply.


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