Moving onto another design, I decided to attempt a tap
thread assembly using thicker (6mm) material this time. The design is easier, but the construction takes more work and tools. Picture 1
shows the tap and die set needed in manual construction phase.
In particular, I'll be using a 2Mx0.4 tap
to provide a fixture for 2M rounded head metal screws; a bit like the ones in picture 2
; the tap device is shown in picture 3
Tapping the cube will involve drilling a hole that is the inner diameter of the screw. The tap is then screwed in carefully by hand to provide the thread for the metal screw. The screw passes through the laser cut hole with no force and then ratchets the other face to join at a 90 degree angle. This is a preferred method of joining wood when using screws and a butt join.
A handy hint when it comes to reusing and storing screws is to use component snap-lock bags that you normally get with electronics equipment. Reuse screws and plastic packaging to save the planet! See picture 4
You can see the SketchUp design in pictures 5 and 6
The following video shows how to snap together objects in in Inkscape to minimise laser cut lines, set some Ponoko specific parameters (like line thickness) and then save as an EPS file.
For easier "snapping" in Inkscape, use File > Document Properties
, select the Snap
tab, and then check the Snap nodes to objects
The final 2D layout can be seen in picture 7
, notice the black lines I use to illustrated shared edges. This layout will be adjusted for Ponoko before submitting (and more designs squeezed onto the template).Picture 8
shows the Ponoko site ready for cutting; notice how the material and cutting costs have risen a little from the previous tutorial because we are now cutting thicker and more expensive material. When I changed the round holes to square holes the costs dropped a little.
Curves take longer to cut and are charged accordingly. You have to make a decision between the aesthetics and the cost of your design.