Octocat Z Spinner - Rotation Indicator for 3D Printers

Wait for it....

A lot of 3D printers these days are equipped with some sort of autoleveling device, to compensate for an uneven or even angled bed. The compensation, however, does not fix the bed level - the printer simply raises or lowers the Z axis to make sure that the nozzle tracks the bed's unevenness for the first and subsequent layers.

If your bed is a tiny bit angled or warped it's a HUGE benefit that very much improves the experience of 3D printing - all of my machines have autoleveling - but there is a drawback. Bed level compensation alters your model as it's printing - the unevenness is baked in - so if your bed is more than a tiny bit angled, your part will be a tiny bit angled too. Similarly, even a properly trammed bed can drift - and if you have autoleveling enabled you might not notice until your parts are coming out seriously cattywampus.

Luckily there is a solution: the Z Spinner. This attaches to your Z axis, and rotates when it rotates - so if your bed is compensating a lot, you'll see it as this octocat dances for all she's worth! Of course, you could just put a tape flag on it, but where's the fun in that?!

This spinner remixes
billyd's Stretching Cat: https://www.thingiverse.com/thing:1565405

and this octopus by McGybeer:
https://www.thingiverse.com/thing:3495390

Supplies

Your 3D printer

Filament - bright color preferred!

Octocat STL: https://www.thingiverse.com/thing:4598590

5mm diameter by 8mm long cylindrical neodymium magnet (3/16" diameter by 5/16" long works with glue)

Superglue - gel seems to hold the best. I use Gorilla's brand.

Step 1: Print Your Octocat!

First step is to print this guy. The STL can be found on Thingiverse:

https://www.thingiverse.com/thing:4598590

and I've also attached it to the instructable.

The tolerance for the jointed tentacles is quite loose - you shouldn't have any trouble printing it.

Personally, I used

.2mm layers
2 perimeters
20% infill

on a machine with a .4mm nozzle.

octocat_spinner.stl
Download View in 3D

Step 2: Installation

The Octocat is held in place with a magnet and glue - really, the magnet is to make sure the glue sticks well and to make sure there's no chance of the peg moving on install.

Test fit the magnet in your octocat. It should be snug - but don't put the magnet in all the way yet!
Glue the magnet to the top of your Z Axis. On a Prusa Mini, this is the rear of the motor - so be very careful not to get glue in the bearings! You can always re-glue if you didn't use enough - it's much more painful to remove excess glue.
WAIT for the glue to dry completely - with gel superglue, I'd give it a half an hour or so.
Put a SMALL dab of glue on top of the magnet, and gently slide the Octocat on.
WAIT another half an hour to make sure everything's good.

While waiting, I spun the Z axis a little bit just to make sure the glue didn't get anywhere it shouldn't. You can also just start a print to act as a timer + spinner - let the robot do the work!