I have since updated to using the M8 leadscrew & remixed cperiod's design of the lead screw nut plates that allow you to use the same Z motor mounts without any changes. You can find his design here: https://www.thingiverse.com/thing:2917730 and I also made a remix of it. It has been work quite well.
I made this for the Makerfarm i3v 10", but it is my understanding this part is the same for the 8" & 12" version also. This is for the i3v that uses M5 threaded rod. I worked on this design a year ago, but just got back to the design recently. I used the design files from the 12" version located here for the dimensions for this: https://github.com/DonKahones/MakerFarm-Prusa-i3v-12-Inch
I mount each plastic z motor mount to the wooden frame with 2 - M3x20mm screws & a locknut instead of the original M3x16mm & nuts. I can make a version for the M8 rod if someone wants that. I pretty much worked that out already.
The plastic coupling is 42mm high with 2mm of plastic between where the motor shaft ends & the M5 threaded rod begins. It connects to 19mm of the shaft. It would be 20mm, but I added a 1mm chamfer at the top & bottom of coupling opening. You should be able to slide the coupling all the way down the motor shaft & it will not hit the motor or the plastic mount.
The procedure I followed to upgrade this was:
Print out 2 Z-MotorMount_Rev31.stl or if you prefer to use the supports your slicer creates print 2 of the Z-MotorMount_NoSupports_Rev31.stl
You should be able to easily break the supports off with very little filing needed. I used a wire cutter to pull the supports at the base away from each other & then use a needle nose pliers as needed.
- If you are going to use my plastic couplers, also print 2 of the ShaftCoupler_M5x20mm_M5x20mm_rev16.stl parts
- Unscrew the set screws in the couplings from the Z motors
- Raise the X-axis up with the threaded rods out of the way & clamp them to the frame some how.
- Unscrew the screws holding the wooden z motor mounts to the frame.
- unscrew the M3x10mm screws holding the motor to the wooden z motor mounts
Before beginning to install this, make sure the plastic z motor mounts fit & file down with a file or rasp so they fit. I only spent about 2
minutes on each mount filing for fit.
- Mount the motors to the new plastic z motor mounts with those same M3x10mm screws
- Before mounting the plastic mounts to the wooden frame insert the M3 locknuts in each mount.
(It is easier to do this now than later). I use the M3x20mm screws to initially pull it in place. I added a photo for this.
- Mount each z motor mount to the frame & tighten the M3x20mm screws.
If you are not using the plastic couplers I provided, attach your couplers similar to instructions below
- Attach M3x16mm screws 7 locknuts to the plastic couplers
- Orient the coupling with the text Up on the top of coupling & press each onto the motor shaft until it is all the way in.
- Unclamp your x-axis as needed & insert the M5 threaded rod into the coupling until it is all the way in.
- Tighten the 4 - M3x16mm screws until they are tight enough
- Check all your connections to make sure nothing came loose during your upgrade. My hotend fan came loose when I was doing this.
- Turn your machine back on & level your bed. That should do it.
I printed my parts using esun PLA+ yellow filament. I used Slic3r Prusa edition 1.40.0 with 40% gyroid infill, .2mm layer height and 3 perimeters. The arch I added to the design to give it a little more strength.
The only wooden parts left on my printer are the large frame parts.