Novena Heirloom – hinge plate construction

 

Veneered hinge plate sliding into LCD panel
Veneered hinge plate sliding into LCD panel

The Novena Heirloom design incorporates an aluminum hinge plate designed to transfer torque-hinge torsional loads to the LCD panel housing. The housing itself is made from a combination of a wood composite material developed for the project and a set of matching solid-wood stiles and a rail along the sides and top respectively. These L-shaped solid members form a slot that receives the LCD when slid into the assembly from the bottom. The hinge plate then follows to form the fourth capturing channel for the LCD. It also incorporates the bottom wood rail.

hinge mount
Mounted hinges on the aluminum hinge plate with lower wood rail.

The custom hinges designed for the Heirloom computer mount to a CNC-milled recess on the inside of the hinge plate. The hinge leaf location is hidden by the LCD enclosure panel during assembly. A mortise for the hinge knuckle is cut into the lower wood rail to provide clearance with a clean appearance. The edges of the aluminum hinge plate form tenons that slide into the slot formed by the wood stiles at the sides of the LCD enclosure.

hinge and reveals

Along with the two hinge locations, the CNC milling operation for the hinge plates includes clearance channels that reduce the mass of the plate assembly and provide room for the LCD cable routing. The back face of the channeled hinge plate meets the inner surface of the composite LCD enclosure panel where a pair of screws attach the two and complete assembly of the LCD enclosure.

tapping hinge holes
Freshly tapped hinge mount holes.

Another reason for the aluminum plate design is the significant overhang at the bottom channel for the LCD. The LCD PCB occupies the lower inch or so of the panel, a space which must be blanked out to reveal just the visible area of the LCD when the unit is assembled. I initially considered using the aluminum plate in its raw state but experimentation led me to choose a veneered assembly to more effectively match the visual appearance of the Heirloom interior.

Veneering the hinge plate.
Veneering the hinge plate.

As is often the case with visually simple design, this assembly proved to be quite challenging to pull off. Matching tolerances between CNC milled aluminum plates veneered with 0.027″ of material and the solid wood and composite enclosure assembly required that the hinge plates be individually trimmed to thickness and face width on the CNC mill. I wrote a set of g-code files with a range of parameters to cover the variability within the enclosure assemblies and then carefully matched each hinge plate to its corresponding hinge plate.

The net result of all this work is a set of beautiful LCD panels with a clean and simple appearance true to the character of the overall design and a sturdy mechanical system for hinging the panels to the bottom half of the Heirloom enclosure. After final shaping of the top and bottom rails and trimming at the stiles, the LCD enclosures will receive finish in preparation for final assembly of the computers.

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