Lathe Cut Santa

Machine Type:

Other Machine

Software:

Vectric Vcarve Desktop

Electronics:

OpenBuilds BlackBox

Machine Time:

2.5 hours

Bit or Laser Size:

Roughing - 1/4" ball nose end mill, Finishing - 2mm ball nose endmill

Feeds & Speeds:

Roughing- 5000mm/min, DOC 5mm, 40% stepover
Finishing - 4000mm/min, DOC 1mm, 10% stepover

Materials:

Arborvitae branch from a tree that died.

So far, I have cut several items with my newly built lathe based on a LEAD High Z kit to get it dialed in accuracy-wise and to test limitations. So, I decided to actually cut something for the holidays. There are limitations to the rotary axis since it is not a true 4 or 5 axis mill. In other words, if there is something sticking out of the model at an angle, the material below the object can not be cleared. In that case two sided milling would make more sense. I have really enjoyed this machine build, It is nice to have a stand-alone rotary axis and overall, it was not to expensive. I used two Cbeams, but I really feel one would have been enough because with the stepover rates I am using, there is not a whole lot of stress. So, If I were someone with a LEAD machine, I would do the High z mod. Then, for the price of the rotary axis and a piece of MDF (or aluminum) with slots cut in, or some t-track, you could build a rotary axis and easily place it underneath.

To the project:

I found this model by ejo on Thingiverse Santa Claus statue, supportless. by ejo

I found piece of arborvidae branch with a suitable diameter. I used 38mm in Vcarve, but some areas were thicker than others. The length was 140mm. I always base my cutting on the cylinder center because my material is not even enough to zero on the cylinder surface. After importing the model, I rotated it on the z axis so the center point cam out the tip of his hat.

I added 3D pyramid tabs that - when stretched beyond the model - form cones at each end. By doing this, I machine away much of the waste material so it is not in the way of my collet when I plunge deep with my short 2mm ball nose end mill for finishing.
After roughing:
For finishing, I drew a vector (square box upper part of the image below) around the area I wanted finished. No reason to waste time finishing the tabs. After finishing:


Here is a video and some pictures. I am amazed at how smooth something is after running over it with either a 3.175mm or 2mm ball nose endmill at 10% stepover. I chose 2mm for this one because it was a smaller model and I wanted more detail.

I finished off the area where the endmill could not reach between the legs with a drill and a scroll saw. Then I cut and sanded off the tabs.