189,5mm from corner-to-corner (motor axel) so not really a 250-size
New frame, 35grams:
Double decker 48gr:
The plugin for Eagle PCB CAD called pcb-gcode is great, don’t get me wrong. But somehow it wants to start the coordinate system so that the X values are negative. Also it made some strange “margin” in Y-axis which makes alignment of the actual PCB to be milled difficult.
So I wrote a tool that can:
See this picture for the original gcode generated by the Eagle ULP:
And then gcode my program generated, reloaded back to the software itself (the green cross indicates gcode x+y zero point). The toolhead still visits to negative Y-values at the start but that’s too difficult to be removed (see the line that goes to bottom right corner):
First attempts! Not perfect but usable.. The PCB moved alot in Z axis.. Traces are 0.4mm – or try to be. That’s probably the safe minimum. Full board size was 71.6mm * 100.2mm (note to self). I used this bit – a 90 degrees 0.1mm V-shaped bit. Drill size was 1mm, should use 0.8 or 0.6mm size drill..
My first adventures in the land of CNC milling was to make a wooden box. I’ve always liked boxes, finger joints and computers. Don’t ask me why.
However the problem with CNC milling is that inner edges tend to come round – for some strange reason. On a finger joint it causes problems; the pieces won’t go to the very end of the joint.
I overcome this by making a little “notch” at the inner edges (see images below). So I wrote a PHP script that generates a PDF that I can use when generating toolpath for the machine. Now I can make different size boxes with just changing few parameters!