I found everything in my scrap: a 1/4" hollow pin, a medium-tension spring that fits freely inside the pin, which luckily gives me 10mm of travel. I pulled out all the disposable pens I could and started testing which tip would fit on my pin, and one fit so perfectly that it doesn’t come out and is completely centered. I enlarged the hole in this tip so the graphite refill fits precisely at 2mm, and I trim the graphite refills to 10mm outside the tip (thanks to the margin the spring gives me).
To define the Z home, in the case of the new refill, I lower the Z axis until it touches the material, then lower it another 7mm, then define the home and return Z to 15mm. To minimize the amount of exposed graphite and reduce the chances of breakage. When generating the G-code, I warn it that the safe Z distance is 12mm.
Please pardon my English, Google is helping me.
I cut a bathroom cabinet with my Maslow, the wood had to be cut on the back to make some pockets and I was surprised when I turned the parts over and saw a crack that crossed almost all the pieces on the front, but I decided to honor this mark of life of the wood, my wife gave me an image of birds from Pinterest and I redrawn it to make a DXF and my first drawing with Maslow,
the pencil test came out perfect, it doesn’t jump, it slides smoothly, it has a constant diameter, it allows me to use Z, because it is graphite I can erase it easily with an eraser, the ink does not dry out, these colored pencils also come in those diameters, when spring-loaded it passes soft obstacles, even if the graphite breaks it will continue to work thanks to the spring, but in the tests no spare part has broken