4. Making the Robot's Pencil Holder

The pencils on the No.2 robot are held in alignment by a tined comb. This prevents individual pencils from sliding out of the region they were supposed to be guarding, and instead bunching up at one end.
Here's how the pencil holder was made:
1. I measured the pencils and created a paper template using the Microsoft Visio drawing program. The template was taped to a piece of scrap aluminum that I purchased from an eBay auction. Before attaching the template, the aluminum was cut to size and cleaned up on a MicroLux miniature milling machine that I purchased from MicroMark.
2. Using the paper template as a visual guide, lower a 3/8 end mill (from an eBay auction, MSC Direct.com, or McMaster-Carr) to check for the proper horizontal position.






3. Raise the end mill up. Cut across the top of the aluminum workpiece, removing a small amount of material with each pass.
While it might be nice to magically cut straight-through the workpiece to create a complete tine in a single pass, the result would be a futile or damaging if you tried it. Metal machining requires patience.


4. Making progress.







5. All right. One tine is complete. Move the backstop on the milling machine to mark the maximum depth so that you'll know when you received the same point on each tine after this.




6. Although this picture shows the second tine being completed, I proceeded in the same methodical manner as the first tine -- cutting down a bit with each pass.





7. Almost done.








8. Ta da!