Almost done with the center amulet.  The only thing that remains is to decide if I need to model the center stone, or deal with it later.  Still also trying to determine the material to make this out of.  Candidates include 360 Brass, or machining a negative of the part in wax and pouring a metal filled resin.  The knot work like sections aren't perfect to the original, but they are somewhat close. 

4 Axis Mill Model

Here is the mill with the 4th axis modeled in Alibre.  Although Alibre can import the older models designed in Solidworks directly, the assembly files do not translate the relationships between parts, making it less useful.  The practice in a new cad system was helpful as well. 
The main reason to do all this work is to finish the design and installation of homing switches.  With smaller stepper based system, these are not required for a mill without a tool changer.   I am working on a tool change system, manual at first, and later automated, so the switches will be needed. 

Finishing up some work on the 4th axis setup for the milling machine.  This was also designed in Alibre (along with entirely remodeling the entire milling machine, a story for another post).  This will allow controlled rotation of a workpiece parallel to the X axis of travel.  One can reach more sides of a part with a greater variety of cutters.  It can also reduce the amount of different setups required to make a single part, saving time and difficulty.  I purchased the rotary table some time ago for use with a manual milling machine.  The standard mounting for a stepper motor will not fit this design, so I constructed my own using a bracket and some timing belts.  Here the rotary table is shown with a collet setup, which allows holding work up to 3/8" in diameter.  A larger capacity chuck is on it's way to hold larger work, as well as non round parts. 

A matrix of holes was drilled in the table opposite the rotary table to allow the use of optional accessories such as a tailstock for work support, or to simply use to mount additional vises or fixturing.    One more part still needs to be fabricated, a sheet metal cover to protect the belt and pulleys from chips and debris.  Although this part does not require high precision to work well, I am curious to see how Alibre's sheet metal design translates into real parts.  

This plate aligns the table shown above with the base of the mill table.  It allows me to either mount this table setup, or an alternate one with a vise.  The dowel pin holes control the alignment so that each one is mounted in the same location it was last.  Flanking each dowel pin hole are two tapped holes.  These holes hold longer set screws which are used to raise this plate off the dowel pins.  This entire setup weighs close to 40 pounds so the screws enable easy removal without damage or injury. 

The same interface will also be used when making a table for working with larger sections of flat stock.  

Starting work on an amulet for my sister.  This is the rough modeling of the center portion.  Still needs more scroll work in the spaces between as well as a center stone.  More to come..

Today I completed the center section, which holds the 4 carbon fiber arms.  It also mounts the controller board, and I will connect the battery pack to the bottom.  Pictured next to it is the stock MQX frame.  The motor mount is a much lower profile unit, sacrificing a little bit on the protection side for a drop in weight.  The large gear is pretty well covered, just no landing feet.