The Floating Credenza – Cabinet Back

Hello and welcome to my blog! This post completes a series in which I’ve built a credenza of American black cherry.  In this post I will detail the process of creating the cabinet back and its supporting framework.  My framework will utilize sliding dovetails in its construction, in effort to constantly improve my process and result I’ve recently revisited my approach to sliding dovetails.  The improvements I’ve made, on the advice and encouragement of Chris Hall (The Carpentry Way), are detailed in this post.

The material I chose for the cabinet back is rift sawn and vertical grain.  I selected this material from wider flat sawn boards, cutting away the rift sawn edges to be re-sawn into thinner boards.  Once re-sawn, these thin boards were then set side by side and glued to create the full panel of vertical grain material.

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The panel was next jointed, thickenessed and finish planed, bringing it to approximately 3/8″ thickness.  Once the panel was brought to dimension my next step was to square the sides, then cut and square the overall length.   Finally I needed to create an air gap between the top of the panel and the top of the case to allow seasonal expansion.  We’re not yet into the driest months, so I did not need to leave much room at all, however to err on the side of caution I decided to leave a little more room than needed.

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Next I created simple moldings for the inside of the case, the moldings act to detail the interior of the case, mimicking the effect of mitered upper corners and square lower edges of the exterior, while hiding the expansion gap from view and holding the panel in place from the inside.

The panel will be captured between these interior moldings and the exterior trim.  The gap shown here between moldings and panel will disappear once the exterior trim and supporting battens are applied to the panel.

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The panel is flat, currently, however any small cup in the panel will show as a gap at the interior divider.  A gap on an otherwise ignored interior surface will go mostly unnoticed, but it has the potential to bring me great shame should it appear and become recognized!  My family would need to retreat toward a quiet life in the hills for many generations until the panel gap has been forgotten.

To prevent this gap from appearing I decided to break the panel up into three sections with dovetailed battens.  The battens, dovetailed into the case back, will allow the panel to move seasonally whilst remaining flat.

Creating the battens begins with bringing the material to dimension.  When working with small pieces of material I like to use my planing beam as a back stop.  The beam, being perfectly flat along the sides helps me to remove any bow from small pieces which cannot support themselves under the force of the hand plane.  The battens are cut from vertical grain cherry.

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The next step in the process, cutting these battens into dovetails, is where I needed to make a change.  My dovetail planes are setup from their respective makers to cut 10 degree dovetails, and normally to create a tight fitting batten I’ve needed to cut a heavy taper.  I’ve been wanting to reduce that taper to allow the panel easier seasonal movement.  Even still sometimes the battens will end up loose at one of their ends, or in the middle, due to the extent of this taper, causing me to remake the batten.

In speaking with Chris Hall, he advised me that in order to improve my sliding dovetails I would need to significantly increase the angle that my dovetails were cut on.  Being that I cut these dovetails with planes, this was no small task.  The determining factor would ultimately end up being my ECE plane and the thickness of its sole.  In order to increase the angle that the dovetails were cut on, I would have to taper the sole more aggressively.  I was able to work out another 4 degrees, bringing the total to 14 degrees.  Once the sole was adjusted, I had to transfer that angle to the blade and grind that down to match.

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The ECE plane cuts the male part of the dovetail joint.  The female side of the joint (the housing sidewall) is cut with an HNT Gordon dovetail plane.  In order for the joint to engage properly the planes should match one another.

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In order to match the planes I first attached material to build up the fence.  Then cut that material to match the angle to the sole of the ECE plane.

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Finally I trimmed it up to match the previous aesthetic.

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With the planes now modified and closer to an ideal setting, it was time to begin cutting dovetails and see for myself what improvement was made.   I began the process by cutting the male side of the joint.

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Followed by cutting housings into the panel, then shaping their side walls with the now modified HNT Gordon plane.

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As the joint came together it became apparent that the new pattern was superior in its engagement.  A lightly engaging assembly (without much compression) was held firm in the housing with no chance of pulling out at the ends, or center, of the joint.

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Shown here, the end of the joint.  I cut a chamfer at the ends of the housing to allow easier engagement.

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Now, with the dovetailed battens in place, I can complete the exterior trim work.  The next step in creating the exterior trim, after bringing the material to size, was to cut overlapping joints at the dovetailed battens.  These joints will serve to capture the ends of the battens between the case and the trim.  I began this process by scribing a line along the batten.

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Next I crosscut this line to form a shoulder.

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Followed by sawing away approximately half the thickness of the batten.

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Next I cut a housing into the trim to receive the batten.

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Once complete the same process was repeated along the outside trim pieces.

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Finally I mitered the outside corners and was able to assemble the cabinet back.  To hold the trim in place, I drilled and chamfered holes and used brass slotted screws along the interior upper edges.  The lower trim was captured from the underside of the cabinet to hide the necessary screws.

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This past weekend New Hope Arts’ held their opening reception which kicks off ‘Works in Wood’ a show in which The Floating Credenza, along with many other wonderful works, is featured.  I had the pleasure of meeting so many great people at the show, including other studio artists and had the chance to put names to faces.

 

I hope that you have enjoyed following along with this build and I look forward to your comments!

You can find more about Chris Hall here on The Carpentry Way.

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