So bare with me here this is meant to be functional and also a learning exercise. My instincts may be wrong but they tell me that the best chance of good function on the Z axis (in addtion ## Issues addressed:) is equal pressure perpendicluar to the sled surface to help prevent offcenter pressure causing binding. Hence my attempt to create a router “hat” as seen below. The idea is to attach three springs to the sled to three equally spaced points on the “hat”. Am I wasting my time, doing it all wrong, or just plain crazy? Let me know. 
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Here is the svg file if interested. Use at your own risk! Well doesn’t seem like I can properly post the svg, sorry about that.
hard to understand what you are trying to do?
Nicely designed and good job! My first thought though is that “hat” is gonna interfere with the operation of the pulleys on the ring. If that doesn’t the springs probably will. Also I don’t think this will prevent any binding any more than connecting the springs/bungee directly to the top of router from the sled in the same orientation you planned for the “hat”.
Edit: this actually reminded me of this 3d printed cap for router
The 3D printed cap sent me down this route as I don’t have one yet (3D printer). The center pocket is full through for the router vent. Just outside that is .4" and will sit flat on top of the router. The small part in front alows for router speed adjustment. The hole on the back is for the z axis motor/controller.
I think I have the springs figured out where they will not interfere. This way I can use 3 and should be able to get the tension equal without spreading the spring or bungee across the top which I think creates unequal pressure on one or the other side. The size of it should make equalizing the springs easier (they will be adjustable). It’s definitely overkill and may not work but I have successfully migrated a design from SketchUp to ground control.
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Excellent I look forward to your progress.
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So time for an update. I mounted the hardware to the final sled, performed the upgrades indicated here http://maslowcommunitygarden.org/Inexpensive-add-ons-for-z-axis-slack-imprecision.html. I used JB weld to attach the bushing to the carrier by putting scotch tape on a 1/2 inch bolt, putting the JB Weld on the bushing and sliding the carrier and the bushing onto the bolt to keep it straight while it set. I installed a washer above the bottom mount for the lead screw but didn’t like how much tension it was creating on the lead screw. I ended up lightly sanding the washer with 600 grit before permanently installing it to lower the tension so that I could turn the lead screw by hand. I was worried about the extra tension raising the resistance on the motor and controller. I sprayed the bottom of the lead screw and washer with graphite dry lube.
I cleaned up the grove in the router base and sanded the entire inside of the base down to 600 grit. Before I put the router back in the base I sprayed it down with dry lube as well. I didn’t want to use anything oily as it sould attrack the dust created by the router. Pictures here What did you do today?.
If you install the bushing be sure to check the safety height in on your tool paths like in makercam so you don’t accidentally run the bushing into the top of the lead screw.
Here are the cutout pics from the project above. I chipped out a little bit of wood removing the tabs.
Here is the inteded installation, the router hat needs some minor tuning to fit all the way down on the top but I am pleased. This was a pretty ambitous detailed project for my first.
I’m not worried about testing the calibration anymore I think it is pretty much dead on.
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Hello! Can you tell me please how can i purchase a Z-axis kit?
Unfortunately I don’t know what suggest. The way Maslows and parts are supplied is undergoing changes, I guess patience is my best advice. Maybe @bar can provide better advice.
Update on the router hat: After several projects under my belt using the router “hat” I am very pleased with the improved performance it has provided. The hat and the other improvements have eliminated the problems with z axis depth control.
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I like this a lot. I’ve had my share of issues here. Thank you for posting.
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@rayner_tavera requested the cut files for the router hat so here is the svg file. You can modify the toolpaths for your own application. I highly recommend adding tabs were applicable. FYI the pocket that sits on top of the router is not perfect I had to make a remove a lititle material with a dremel (sorry, it is free lol).
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