Fabrication Details
Small shaft
Made from 2.5" aluminum rod. First we used the vertical band saw to cut off the proper lenght we needed. We then attached this to the manual lathe, which spins the rod at a specified rotational speed. As it's spinning, we near a cutting tool to the spinning rod to cut it down to size. We trim the radius down about .1" at a time, and bring the cutter down the length of the rod. We make however many passes are necessary, taking off .1" radially at a time.
Main shaft
Fabricated the same way as the Small Shaft, described above.
Copper arm heads
Machined from .5" copper rod. We trimmed the rod down to the proper diameter of the arm heads using the HAAS lathe. The HAAS lathe operates similar to the manual lathe, only it's controlled by a computer. After the diameter was trimmed down, we rounded off the ends of each head by using a certain function in the HAAS lathe's computer. We specified the radius of curvature, and it rounded of the ends as needed. After we'd round the end, we'd use the band saw to chop off the proper length of the head from the main rod, then do it all over again. Once we had all of our heads, we used a drill to drill a hole into the bottom of each head using a drill bit on the manual lathe.
Copper Contacts
Also machined from .5" copper rod. Rod was trimmed down radially to the proper contact radius. Then we used the band saw to cut off as many contacts as we needed. We then took each individual contact to the lathe, and used a .25"-radius round bit to cut a concave arc into the ends of the contacts.
Base Plate
The Base Plate was machined from a spare aluminum plate from the machine shop. Using a spare plate allowed us to fabricate the part for zero cost. A vertical band saw was used to cut the plate to its proper length. A drill was then used to make the appropriate holes for mounting bolts. A mill was used to extend some of these holes into slots.
Plexiglas Walls
The Plexiglas walls were cut from a large Plexiglas sheet that the Team ordered. A vertical band saw and a Dremel tool were used to cut them to shape. Holes were drilled using the drill press.
Tap Changer Shell
The shell was machined in two halves from a single block of nylon using the CNC mill. MasterCam (software) was used to program the tools and tool paths needed to cut the shell haves out of the block. The MasterCam file was imported into the CNC Mill's computer. Any excess material left on the shells was cut off using a standard mill. The standard mill was also used to cut all of the holes into the shells. At a late point in the construction stage the sinusoidal pattern on the interior surface of the shell was removed with a Dremel tool equipped with a diamond grinder.
Geneva Gear
The Geneva Gear was machined out of 3/8" thick aluminum block on the CNC mill using a MasterCam file.
Geneva Driver Gear
The driver gear was machined from a block of nylon. It consists of two parts, both of which were machined on the CNC mill.
Small Shaft Support
The small shaft support was machined from a spare aluminum block from the shop. A vertical band saw was used to cut to dimensions, and a CNC mill was used to cut the appropriate holes through the center. Finally, a drill press was used to cut the smaller mounting holes off to the side.
Arm Collars
The arm collars were machined from nylon using the CNC mill. The contact spring assembly holes, as well as the wire access holes, were drilled using a standard mill. The set screw mounting holes were drilled using a handheld power drill.
Helical Stop Arm
The stop arm was machined from 1/2" diameter aluminum rod. A vertical band saw was used to cut to appropriate length, and a lathe was used to trim to the correct diameter.
Helical Stop Arm Guide
The arm guide was machined using spare aluminum block from the shop. A vertical band saw was used to cut to appropriate dimensions, and a mill was used to cut a slow. Two mounting holes at the bottom were created with a drill press.
Main Shaft Top Bearing Support
This part was machined from spare aluminum from the shop. A vertical band saw was used to cut to length, and the center holes were cut with the CNC mill. Two small mounting holes were created with the drill press.
Main Collar Shaft
The helical groove in this part was cut using the CNC mill, applying the 4th axis principle. The shaft rotated while the endmill cut along a straight path, creating a helical end product.