Motorized precision macro rail

I recently got into macro photography and my (pretty old) camera has no integrated focus stacking options and is generally hard to focus without moving too much. I first bought a cheap rail, but unfortunately that was a waste of money, it was exeptionally cheaply build. Better ones come with a hefty price tag. So I decided to build the best one I can do for around 100€.
I did not design this for others, this is a tool used by me, but I thought maybe it can be useful for some:

3d printed body, printed as one part on the mk3s to increase stability, I used PLA. No part should need supports, prints well in 0,3mm.

easy to assemble, parts worldwide available (but metric, possibly interchangeable)

Compatible with this arca swiss adapter https://www.printables.com/model/251614-strong-arca-swiss-clamp

optional: I want to use this controller, it includes a magnetic rotational encoder: https://thingsbyjosh.com/products/pd-stepper 

this comes without software and I cant provide it. pls use whatever hardware you want to control the stepper eg. arduino or esp with driver, cnc shield etc. and look into their documentation what settings you need to change.
usually: microstepping, step count for 1mm per 1 rotation with microsteps, the endstop, the drivable length of the rail (around 160mm), travelspeed and drive speed (go slow to reduce vibration and be precise), motor power.

Parts list:

a typical switch for an endstop.

24x M3x10 socket head screws for nema17 and the rails

8x M3x8 socket head screws for the slider

2x M2x8 for the endstop, may be different, can also be just glued in place

2x M4x16 countersunk screw (for mounting the arca swiss mount)

2xM4 Nut
+the screws listed in the arca swiss model.

200mm MGN9 linear rails

220mm self locking TR6x1mm trapezoidal spindle directly driven by an NEMA17 0.9° stepper motor should get you more than enough precision. I used a standard full length spindle without machined ends because its cheaply available. I havent tested the smallest possible linear step, for my setup 0,1mm is enough at the moment. typically you can find these on aliexpress or amazon. Make sure it has an 1mm pitch!

1x 5mm/6mm aluminum coupling or a 3d printed version of your choice, check what size your motor has, there seem to be different.

2x 607 bearings. they dont fit perfectly to the spindle, but I fixed it with some plastic. Its not that important as the rails provide the stability. Otherwise you would need a lathe or custom made spindles and for example 626 bearings but thats expensive. You could probably use 3d printed ones.

I recommend using the right lubrication for your rails/carriages, I use Klueber MICROLUBE GL 261, not recommended but you can use the same for the spindle, just a bit or just normal grease. Its not advisable to use normal grease on a linear rail. Some carriages come prelubed. 

if you install the sled the first time, dont tighten the screws on the rails beforehand, best to just screw in first and last screws for a bit, install sled, check if it moves free along the rails and tighten after. NEVER remove the carriages from the rails, they get damaged by that. Use the short plastic rail they come with to slide it on the rail if you buy them single. 

If everything is mounted nothing should move on its own, but the spindle should be easy to turn. Make sure its all aligned properly. The spindlenut can be different from each seller, I hope yours fit, I didnt include screw holes because of that, but they are not needed anyway. The nut can slide a bit up and down to align, but make sure its not sliding back and forth. I glued 2 feet under the nema17, probably not needed.

Things that may change:
Currently this machine only works sitting on a table, but Im thinking about some tripod mounting options. I tried to mount it with a single ¼" tripod mount but that was not stable enough. I included holes in the corners, if you want to mount it somewhere.

The rail screws are not fixed, I just screwed them in the plastic which holds enough for me. If its too loose maybe add some glue. maybe I add pockets for nuts?

Warning: 

I take no responsibility for damaged camera equipment! 
Print and use at your own risk!