The Tiny Wheel Trinket

A friend of mine, who makes jewelry, recently laid down a challenge for me to create something "crafty".  Being an engineer, I am anything but artsy, but I gave it some thought and after a few hours playing on the mill I came up with this:

It was suppose to be tiny wheel, but my first attempt did not turn out so well.  As you can likely see from the photo above, while doing the various machining ops, I lost my zero on the DRO and when I went to drill the center bore and lug hole pattern, they were off center.  In addtion, the center bore was too big and the lug pattern ran into it due to the flex in the drill bit I was using.  So I punched out the whole center and chocked it up to a learning experience.

Discourage my mill lost its zero and knowing that I could not sleep well without figuring out why, I headed back to the garage around 10:00pm.  It didn't take long to conclude that the likely culpirt was a loose gib on the X-axis.  (The Y maintains a perfect zero.)  After some adjustment, I was up and running again.  Now encourage, I pressed forward with a second attempt at producing a miniature wheel.  This time I drilled the lug holes first using a center drill to lay out the pattern followed by drilling the hub bore after double checking that I was still on center.  This worked much better aside from the 1/16" bit snapping off in one of the holes.

My second attempt still needs polishing, but it turned out much better than the original and makes a cool desk trinket.  I was even able to punch out the broken drill bit after milling the backside counterbore.

Update 1/28/13:  I finished a few more to hand out to some friends and one made from aluminum which turned out nice.