Tuesday, October 8, 2013

Mission Desk - Design, Milling and Sizing Lumber

I began designing this desk during the fall of 2007. As most projects go, other priorities changed my schedule. Construction began the spring of 2010. The project was finally finished January 2011.  My projects take way to long to complete.

Since my daughter was born in Texas, I choose two native species to Texas. The primary wood is Mesquite, and the secondary wood is Pecan, the Texas State Tree. This was my second project using Mesquite. I love its rich color and beautiful grain. However, I wouldn't recommend this wood to anyone. It's full of flaws, holes, cracks, and it is expensive. It's difficult to find stock 8/4 (and larger) that's very long and unflawed. This project required Mesquite veneered panels, which are almost impossible to find commercially. Luckily, I found a source for Mesquite veneer at Texas Mesquite Lumber in nearby Willis, TX.

I'm not sure if it's a rule, law or just coincidence, but it seems like every project requires a new tool, jig or both. This project required the construction of a Veneer Vacuum Press. As the name implies, this pump is used to create a vacuum in a vinyl bag to press veneer during the gluing process. The plans and parts were found at Joe's Woodworking and VeneerSupplies.com web site. You can see the Vacuum Press in operation in the photo at the right. I'm pressing one of three panels for the desk top.

Veneered panels were needed for all sides of the desk with the exception of the drawer fronts which is solid wood. The desktop required three veneered panels which were framed with solid wood.
SketchUp View of Desk
SketchUp was used to design and draw the plans. To assist my design, I referenced several books such as "Stickley Craftman Furniture Catalogs", "Shop Drawings for Greene & Greene Furniture" by Robert W. Land, "The Furniture of Gustav Stickley - History * Technique * Projects" by Joseph J. Bavaro and Thomas L. Mossman, and I also purchased plans from "The New Yankee Workshop" to study the construction. Although these books and plans were all useful they only inspired the final plan.

After a short time I realized that this style of desk has a major design flaw. One side of the outer drawers are solidly supported on one side by each leg, but the support on the other side of the drawer less sturdy. The inner support is basically hanging from the front and back top rails. As a result, I reinforced several of the joints with Knock Down Hardware (2" bolt + cross dowel).

Milling and Sizing the Lumber

There are 119 pieces of hardwood and plywood used to construction of this desk. The majority of the hardwood was milled to a 7/8" thickness. The seven side panels are 3/8" birch plywood, and the desk top is constructed of 3/4" birch plywood and Mesquite framing. The legs are 2 1/4" x 2 1/4" x 29 1/8". The overall dimensions of the desk are 30"H x 31"D x 67"W. The desk contains 43 board ft. of Mesquite, 25 board ft. of Pecan and 39 sq.ft. of plywood. Mesquite weights 50 lbs/ft3, and pecan weights 47 lbs/ft3. The total weight of the desk is estimated to be 350+ lbs.

The legs were the first parts that were sized, and all mortises, dadoes and other joinery was cut. All the other parts of the desk were sized to fit the joints of the legs. It's important to label each leg to prevent errant cuts. I used veneer tape to label the outsides of each leg. Although each leg was accurately cut to length, I made all measurements from the top of the leg.

Each of the front legs has a two through mortises, and the back legs have three. These mortises should be cut with a mortising machine from the outside or face side of the leg just in case you get blowout when the chisel exits. It's also important that each side of the legs are square. Otherwise, the chisel will exit in the wrong location.

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