[dracozny]

yea I bought the anti-backlash (aka doublenut) screws. I had to completely redo the spacer on the Z screw, so in theory the nut should not be the cause at all, but anything is possible. The spacer I made includes two bellville springs to compensate for loosening tolerances over time.

[dracozny]

Finished up the Y axis today. I wound up with a few snags to work through. one of which is the Pulleys I purchased did not have the option for a flange. I knew this might present a problem later, and sure enough it did.

Yes that is the top off of an old mason jar. it does the trick and the top side is smooth enough that it isn't chafing the belt. I only needed the one thankfully. The motor mounting plate has a bit of flex in it after tensioning the belt even though it is 1/2" plate which is why the flange is ultimately needed.

I needed to make some room. I wanted to enlarge the Y travel so I ordered a long enough screw. This cut was about as lazy as I could achieve. I'm sure if I just dismantled the Mill and flipped the base over to make the cut it would look much nicer, but I really did not want to deal with pulling the column again so this method requires drilling a series of holes, cutting the left and right side into the drilled holes with some sort of saw. In this case I used a Fein Multi-master. The remainder is sheared off using a wedge through one of the middle holes. Physics wise this is not too dissimilar from rock and marble removal in a quarry. The jagged edges were cleaned up some just to avoid cutting myself if I ever need in here in the future.


After bolting this all up I moved onto tuning. for some reason the holes I cut in the motor mounting plate always ends up being too small for the damn nuts that came with the ball screws as I will always find some amount of rubbing from the corners. I am trying to give the X mount a little more clearance as I type. I still wound up with .006" of backlash. since this mount is much easier to get to in comparison to the Z I was able to apply my magnet base and Shars dial indicator to figure out what specifically is moving. as I suspected the ball nut mount is still sliding back and fourth against the saddle. there isn't a whole lot I can do unfortunately other than remaking these parts and attempt to be much more precise with the inserting protrusion. my only other thought is some sort of epoxy filler to take up the gap. on the Z the protrusion was never made onto the mount, instead I have a tight fitting washer filling the hole in the slide. So the backlash is the result of the Bolt tilting up and down. I could weld these two parts together and that should eliminate that particular issue. As it is the computer has been calibrated to adjust for it, although smaller movements less than the found backlash are impossible to compensate for.