Thanks, Neil, for the kind words.
IMO it seems inherently right and proper to engrave a useful and reasonably accurate ruler when setting up and calibrating a CNC laser engraver... and I have them laying all around so one is always easy to find. Virtually all my 3d prints and milled CNC parts need to interface with standard hardware and my enjoyment level goes up by leaps and bounds when well-fitted parts, fabbed on calibrated machines, mate easily and accurately with the hardware that holds it all together.
Before you ask, most of my rulers are 152mm (plus a fraction)...it's an "artifact". My very first rulers were 6" rulers, of the "imperial on one side, metric on the other" variety you mentioned. When I chopped off the "inches"-side, I was left with a 152mm scale, which I then duplicated and flipped, to create the "2mm offset sides" ruler shown below...
I honestly wish that the US had completed the transition to the metric system that was being pushed when I was young but, alas... they didn't and, an older US citizen now, I grew up using imperial measure almost exclusively. Once I made the decision to pursue engineering in school, however, it didn't take long to become comfortable with metric measure and I realized quickly that it is a far easier/better system to work with. I use it almost exclusively with my technical, hobby-related, activities -- 3dprinting and CNC -- but, even now, I must admit it's still easier for me to picture/judge a 100-yard [American] football field and play golf with yards to the hole rather than meters. Oh, well...
Thanks for the tip regarding oil-board/stencil-card... I've got a small quantity on order now. I use craft sticks for a lot of stuff but cross-stitch patterns really weaken the wood, especially along the grain... and thin plywood takes longer to cut with a diode laser. Also, I'll have to try your octagons vs circles trick...
I've gotten the Eleksmaker A3 converted over to Marlin/RAMPS from the GRBL-based firmware and controller that came with the machine. I know that some will say that is a step backwards but it now has a fully-implemented Z-axis and, being for my daughter, it is compatible with my Marlin-based MPCNC machines that I've used for most of the cross-stitch and stylized image work I've done so far. Here's the new Z-axis running over its 60mm of total travel... it's a bit noisy yet (it uses BB "bearings") but it's reasonably smooth and getting quieter with use
The stylized images I've been playing with are *vector* images created with a neat set of Python extensions... called "Blackstripes Python Extensions" out on Github
https://github.com/fullscreennl/blackstripes-python-extensions
There is a thread over on the V1Engineering forum where I first learned of this... you may want to check it out
https://www.v1engineering.com/forum...res-into-stylized-svgs-suitable-for-plotting/
A great advantage is that, being vector images, they are relatively quick to print (vs. raster) and yet still quite recognizable. Effects utilized are crossed, spiral, and sketch... crossed and spiral are my favorites so far.
Later.
-- David