# Need Advice on Live Edge Bookcase



## Th961605 (Nov 25, 2013)

I'm working on a bookcase which will consist of two bookmatched walnut slabs and solid walnut shelves spanning between. Since live edge is being used, plywood would be out of place, so I'm wondering how best to join the shelves to the upright slabs. I don't want to use pocket screws with oversized holes, but I'm debating on which form of joinery will allow for some movement and still be sturdy enough to support weight. Are dowels the best way to go here?


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## JBrow (Nov 18, 2015)

Th961605,

A joint that might work well in this situation is the sliding dovetail joint. Cutting away a ¼" or 3/8" off the dovetail tongue at the front of the shelves and then gluing only the first 1" or two of the dovetailed tongue to the dovetailed groove at the back of the slabs would allow the shelves to expand and contract toward the front of the bookcase. The dovetailed joints would help hold the slabs in position mechanically.


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## Lazyman (Aug 8, 2014)

Approximate dimensions might help.


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## BHolcombe (Sep 19, 2012)

Through tenons, wedged on the visible side.


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## Th961605 (Nov 25, 2013)

Each piece will be approximately 48"x14"x1". I'd like to keep the exterior sides of the live edge clean, so no through tenons (although I do love that look on non live-edge). I really like the idea of sliding dovetails, although a router table isn't an option on these pieces. Would a simple dado cut (with extra room towards the back) be enough to allow for expansion? Is there a good way to allow for this with a mortise and tenon?


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## JBrow (Nov 18, 2015)

Th961605,

The stopped dado in the slabs could house the shelves, but would not provide any sideways mechanical strength to the joint. The strength of this joint would only come from the first 1"-2" of glue applied to hold the shelves to the slabs. The 1" -2" of glue can be applied toward the front edge or back edge of the dado, depending on whether you would want any expansion or contraction to occur at the front or back of the bookcase. If the bookcase has a back, expansion would be better at the front of the bookcase since the back would stop expansion unless a gap is allowed at the back during assembly.

The router table would be handy for router dovetailed tongues on the ends of the shelves. However, a straight edge guide would be my choice for routing stop dovetailed dados in the slabs.

The mortise and tenon joint could be used. The tenons would have to be narrower than the mortise to allow for expansion. Only the rear-most or forward-most tenon would get glue so the remaining tenons would be free to move within the oversized mortises. But the problem with this joint is that tenons would have to be cut into the ends of the shelves and the shelves would only be supported by the tenons. Therefore, if this is your preference reconsidering the dado joint may be worthwhile. The dado joint would be easier cut and would provide downward support all along the joint.


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## Lazyman (Aug 8, 2014)

If you attach a back on it that will prevent it from racking, the shelves don't have to be firmly attached to the sides-only the top and bottom need to be attach. You could even use shelf pins or just attach strips for the shelves to rest on.


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## JBrow (Nov 18, 2015)

Th961605,

I am not sure what I was thinking in my two prior posts. I think the shelves can be simply glued in place with whatever joint you like. Wood movement is not a likely problem.

The grain in the slabs that form the sides will run vertical. As the side slabs expand or contract the movement will be front to back. The grain in the shelves will run from one slab to the other and parallel to the back and front of the bookcase. The shelves will therefore also expand and contract front to back. The shelves and slabs are both walnut so the rate of expansion and contraction should be roughly the same, assuming the slabs and shelves are close to the same moisture content.


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