I would like to engrave lettering and artwork on my reels. The engraving done at jewelry stores is not satisfactory; I want deeper cuts. My artistic talents are not sufficient to allow hand engraving, so CNC seems to be the best approach. There are commercial machines available, but I don’t like the cost and lack of capability so I am designing my own machine.
I now have a design on paper but am uncertain if it will be satisfactory, so I am first fabricating one axis of motion.

Here you see two aluminum plates and two linear slides. The plates are 1/2″ MIC-6 from McMaster-Carr, 6×6 and 6×12 inches. McMaster saws these (I assume) and specifies 1/8″ tolerance on length and width. Mine arrived much closer to the nominal, with very good squareness of corners. McMaster must have a good setup for sawing. Because the length and width of the plates is not critical in my design, I am not going to try to mill the saw cut edges but will just smooth them with a belt sander.

The linear slides are from China (search “16mm linear slide” on the big auction site). Engraving with a high speed spindle will create a lot of fine dust, and I am uneasy about using ball slides. If they fail due to dust, my fallback position is to make replacements of solid acetal. The ball cages of these slide blocks are moulded plastic and include rail wipers, which will be of some help. Another feature is two set screws that distort the cages to adjust out any loose fits.
If this slide (Y axis) is satisfactory I will order material for the rest of the structure, which will have similar X and Z axis slides.