A while back, I tried to enumerate the 2D shapes with an eye towards what shapes one might encounter while automating cutting things out:
Exending this into 3 dimensions arguably would be useful as well, though it does create further difficulties in terms of nomenclature.
Looking at typically available CAM tools we find that there are certain things which are usually readily cut in a CAM tool:
circles and rounded forms w/ flat bottoms:
rectangular forms w/ rounded points w/ flat bottoms:
arbitrary shapes which do not have any acute points which cannot be cut by a round endmill — obtuse points can be — consider a star shape, the points of the star cannot be cut w/ a round endmill, but the internal angles can be, since the endmill moves around the angle.
forms defined by the surface geometry and the angle of the V endmill used for V carving:
The pockets above may easily have rounded bottoms added by insetting the geometry as needed to allow for cutting the bottom of the perimeter w/ a ball-nosed endmill as seen in:
Cutting past the stock along two edges will allow flat bottom geometry w/ square edges as is needed for fingerjoints as is seen in:
Working up a tutorial on this for the wiki which when it is done will be at:
https://www.shapeoko.com/wiki/index.php/CNC_Finger_Joint_Box (once the wiki comes back up)
First step is to create the box itself: This is done in OpenSCAD using the parameters:
length = 6;
width = 3;
height = 4;
thickness = 0.375;
Next resolve the pin/joint size and spacing:
Next step is to work out how to get from the above parameters to a f…
(requiring a fixture for holding stock vertically)
Advanced V carving allows for flat bottomed pockets w/ angled edges which match those of the selected V endmill w/ a bit of additional rounding.
Other geometries either require special tooling and forgoing a 3D preview or 3D modeling them, e.g.,
Okay, I’m revisiting my flag case project for Memorial Day — this requires a 22.5 degree angle to be cut into the ends of the bottom/sides — in theory a 135 degree V endmill would do this, but it would require a couple of stacked V carving toolpaths, and my wife is on an austerity campaign which does not bode well for buying more tooling.
Is there a tool which makes doing this w/ a ball-nosed endmill straight-forward?
I suppose I should just program something…
Next up is more boxes, this time for magazine storage — for my part I just cut open Fed Ex boxes:
But they’re not always available in a suitable size for typical magazines.
There are a number of commercial options:
So there is certainly precedent for wooden boxes — we’ll try for an inexpensive material, since this is going to be a fairly large project (sorry Nomad owners) — Luan Plywood is available at most home centers, usually as underlayment, a bit of care…