So I did a quick an dirty prototype tonight and it (mostly) works! It literally took about 30 mins start to fin. Note I haven’t even built the frame for my Maslow yet so… 
Up side
- simple and easy to build from scratch
- potentially on this model the Z-axis motor can be directly bracketed off the router itself and not sled which would simplify things.
*Travel is only limited by the lenght of the tubing (see the build below)
Down sides
-
Raise and Lower seem to be reversed for some reason but the is a future me problem
EDIT SOLVED! Thanks to thispost, TLDR; use a negative number for the z-axis pitch. -
My router stuck a couple of times raising but that probably has more to do with the fact the thing is +15 years and the linear rails have some corrosion from contact with the springs.
So the build log for my test!
Parts list (for me)
- 1x 80mm M5 bolt. This matches the existing post on the Ozito and simplifies things, the newer models or other brands may differ.
- 1x M5 nut, I recycled the one off the Ozito router.
- 1 or 2 washers (optional) as a bearing surface… this kind of worked.
- 1 length of 10mm tubing. I used Aluminum as that was all that was available at Bunnings, steel would probably be better but Al worked fine and it was easy to work with.
First this to do is remove the tallest stop in the base, the depth gauge and screw handle used to lock the depth gauge. I used the tallest stop because the thread in the base is the longest but it really doesnt matter which.
I cut a lengh of the tube. I had no idea how long I should make it so I guessed. As it turns out my proof of concept one is a little too short, it probably needs to be in the region of 15 - 20 cm or so. I ground down one end slightly on my bench grinder but a file will do the same job, this was due to it being ever so slightly too big for the shaft coupler.
Next step is to press the nut into the other end of the tube. to do this I inserted an 8mm drill bit (or what ever fits your tubing) into the pipe section. This allowed me to clamp the tube securely without crushing it.
Next I threaded the nut onto a short section of thread (it was actually the short post off the router) and used some multigrips to grab the thread.
I then use a hammer to press the nut into the end of the pipe being careful that it was centered and square as I went.
Aluminium has a tendency to deform so I used my bench vice to press the tube back around each side of the nut. The nut was loose but that really doesnt matter in the final assembly. If it was a mild steel tubing it probably would have pressed in and stayed.
Lastly I cut the head off the 80mm bolt. I would have preferred to just to buy some all thread but it didn’t come in metric sizes.
To assemble I threaded the 80mm bolt into the post base and then added the 2 washers and the nut and sprayed the whole thing with silicon lube including the router posts to make it move more smoothly.
The washers gave a smoother bearing surface than the sintered metal body of the router and to give a flat surface for the nut to press on (rather than the oversized hole that was there.
Below you can see how the tubing with the now pressed in Hex couples to this assembly
Lastly the tubing was inserted into the shaft coupler and motor. The fact the nut came free made this a whole lot easier. As noted at the top the tube is either too short or I need to trim down the thread as the thread travels up the inside of the tube and hits the coupler before the bit is all the way down, I will probably do a bit of both once I know the length of the longest bit I will be using.
At to show it all works!
There didn’t seem to be any torque issues with the motor at all that I could see. Only issue was the hex heads of the coupler hitting the body of the router but that wont be an issue if I mount the motor higher.
Improvements
- Use Steel tubing (when I can get it)
- Lengthen the tube to increase available travel
- Possibly replace the thread with a different thread with a higher pitch to increase travel speed, this would require cutting a new thread in the base which has some small risks of trashing it. The current thread is very fine (0.8 pitch) so raising and lowering is very slow.
Things that didn’t work
I tried to remove one of the springs on the router to reduce the torque the motor needed, only 1 spring wasn’t strong enough to raise the body of the router, however. This may not be an issue once it is mounted on the sled as it will be horizontal (mostly) so I will retest once I have built the frame and calibrated everything.