This time it will be a short entry about the milling machine and Z axis changes. Two weeks ago I received my 300mm long 20mm linear rails. I ordered them in the first place because the supported shafts had too much play, and thus the dimensions in y axis were a few hundreds off. New design is a lot stiffer and has roughly 140mm movement range comparing to 110mm achieved on supported shafts. The most important thing is that they have no play that can be seen with the naked eye. I will share the results, when I do the measurements using dial indicator. Again the parts were milled from a plywood plate on a bigger CNC machine in order to detect any possible issues without spending a lot of money on the materials. Some photos as always:
Z axis before modification
Linear rails in place as well as the ball screw
Finished!
Another thing I guess is worth sharing, is the chip protection for the lower linear rails and ball screw (y axis). I wanted to make curtains following the table - something similar to window blinds. I had to prepare a mechanism for folding and unfolding the curtains when the table moves. The simplest idea I came across was to use torsion springs from cheap folding rules. I 3d-printed my own casings, inserted the springs, added a bearing on each side and used a pvc tube as the shaft. The curtain is mounted to the table using slats with a few screw holes. The whole thing is quite nice-looking and most importantly keeps the chips away from the rails and ball screw.
Mounting process
Inserting the spring
A video of the solution:
The last thing is just an interesting video of drilling using a blunt drill. When you look closely there is a visible heat wave coming off the hole when the drill pushes down on the part :)
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