The neck section was made from MDF and softwood. Although quite wastefull to keep cutting rings, all the centre pieces were used on other parts. The sizes were all estimated from photos.
At the top of the neck section are the 2 motors that drive the head around and the brushes that connect to the head so that it can spin continuously. There are 6 brushes:
1 & 2 = the eyestalk motor,
3 = voice lights,
4 = Eye LED com signal (signals PIC to change colour),
5 = +12v
6 = common ground
Cutting Neck Rings:
Edges were angled with a router and then sanded to produce a round egde.
The 3 rings were cut from 18mm MDF. Then the centre removed with a powered fretsaw.
The cut ring and waste centre part. This was used for other features of the dalek.
Slots were cut to accomodate the 6 vertical struts. Note the blade was reversed to make cuttung easier. This ensures all slots have even vertical sides.
The vertical struts cut from softwood and slotted to fit to the rings.
Assembling the Neck Rings:
When fitting the rings together, care was taken not to split the vertical struts along the grain when pushed and glued into place.
The top ring was glued and screwed into place. This ring will support the motors to enable the head to rotate.
Making the Strut Collars
The strut collars were cut from 18mm thick square MDF pieces. These were sand to produce a 45 degree chamfer over half the collar.
The sander platform was angled and a guide G-clamped into place to ensure consistency over all collars.
Finally the slot was cut for the strut and all pieces were sanded and sprayed indiviually, before being fitted.
Head Guide and Drive
The tram on the head rests on one idle wheel and 2 drive wheels. The wheels are from a printer we dismantled and have rubber rings on already. The shaft was cut to size and supported with a block of nylon shaped and drilled. Nylon is almost self lubricating and provides a trouble free axle mount.
The 2 motors came from printers also which are remarkably quiet even if not much torque. The holders were shaped from MDF and the assembly mounted on a 4mm MDF plate whose position could be adjusted or even sprung to apply the correct pressure to the rubber wheel.
This shows one of the motor assemblies in place mounted on the pivot support frame, similar to the one in the head. Here is a clear acrylic bush for the pivot to sit in.
Here also you can see the black rubber matting that was used to obsure the view between the rings.
The difference in size between the drive wheel on the motor (which is a toothed belt sproket) and the rubber belt wheel provided about 9:1 reduction. This is larger than the drive wheel which is mounted on the same shaft giving a little more reduction. The overall speed was perfect. About 1 head turn every 1.5 seconds.
The brushes were made from brass brazing rods bent and shaped. They were secured on an MDF bracket with 4mm bolts. These bolts were also used for wire connection. The brushes were kept in position by a clear acrylic frame screwed to another MDF bracket. This bracket slides backwards and forwards about 10mm to enable the brushes to widen to assist inserting the pivot pin between them. By reaching inside the neck afterwards, the frame and guide can be slid back, allowing the brushes to rest ont he copper tracks on the pivot. HOwever this technique proved a pain, so I just resorted to care and gentle easing the pin into place - lot easier.
Right: A view of the head pivot inserted into the brushes without the head attached.
Two half decent 4.5 inch speakers were used for the high frequency range sound. They were driven by a 30Watt dedicated amplifier with a bass cut filter. More details on the Sound page.
The speakers were fitted to wedge shaped pieces of MDF and mounted face down at the top of the neck. The hope being that the sound wound eminate from the neck section through the black matting.
The neck section finally completed with the brushes, drive motors and speakers attached.