Machining (Art)
Copper Heart
There is someone I care a lot about. I thought I would try and make a unique gift that references an inside joke. That is all the backstory you are going to get.
A Plan
The dream, of course would be to have the base be red, in line with contemporary Valentines day tradition. Copper comes close enough. For flair, the heart-shaped base received 5 interlocking gears held in place by gold-colored tacks. For extra-flair, each gear was machined out of a different material.
The term “machine” is the verb used to express the removal of material in a controlled way from some larger piece of material, presumably with a machine.
Copper
For those unfamiliar with machining, copper is one of the trickier things to machine. Unlike a lot of other metals, the chips are “sticky,” they tend to clump together and clog the machining surfaces. What this means typically is one much scrupulously clean the machined surfaces after each pass to remove chips or else subsequent passes can result in uncontrolled motion of the part or shattering of the tool bit.
Heart-shaped Base
This shape is not the most complicated shape. It was constructed out of two circles and then closed by the intersection of two lines tangent to the circle-lobes. The angle made by the “v” was chosen purely by aesthetics. Of course, it would be very straightforward to load this into a CNC program, but where is the fun in that? I liked the thought of putting in the effort to really hand make this piece and so I forsook the CNC and used purely analog tools (with digital location read-outs) to machine the base.
CNC stands for Computer Numerical Control and refers to a machine tool that is outfitted with motors and control software to execute motion independent of the user manually actuating the physical components of the machine tool.
The shape was achieved solely through the use of a rotary base on top of a vertical milling maching. The v-shape is just a rotation of the rotary base and then movement of an axis of the milling machine bed. The semi-circular lobes were achieved by centering the part on the rotary base and then spinning it to cut out the circumference of circle. (See below images)
Video tracing out the end mill path using the rotary base.
The keen-eyed viewer may have noticed pieces of black sheet metal between the clamps and the copper. That was to keep the clamps from creating deep grooves in the soft copper and marring its surface, I wanted it to be super fance.
With the shape now roughly correct, I went to the vice and took a swiss file to the area where the lobes meet to create a sharp v shape. Swiss files are not big and I had to remove a lot of copper so this part took a while, but it was worth it.
The gears
Because of the complexity of gears and the difficulty associated with machining them properly, here I decided that the CNC was probably the best course of action. Because I would be removing the edges of whatever shape I put on the CNC mill, the clamping down was down via a screw through the center of each piece. Ultimately, I started this process with 6 pieces of material, all 1/8’’ thick with a hole drill through their centers.
These were machined in pairs, one material at a time:
With all the shapes cut out, it was time to make all the pieces shiny and polished.
Putting it all together, I was really happy with it and I was very excited to give it to the intended recipient.
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