Project Leonard – Z Axis Issues

Well this evening I hit the first snag in the Leonard build. No matter how much I tightened the motor to 8mm bar couplers the bar would not grip. I even tried wrapping tape around the bar in order to increase diameter (yup a dirty hack) but alas to no avail (bad design and/or model implementation if you ask me).

Eventually one of the couplers snapped due to purpose over tightening (not surprisingly) and this brought a halt to proceedings for most of today’s build. The above image shows the snapped coupling. Despite this issue however, I decided to continue mocking up the axis so I could get a feel of how things go together ready for my next attempt.

Once completed I decided to have a go at developing my own coupler utilising the “more durable design” developed by Chris Hanton and as suggested at

The following images show what I came up with:

Fig 1: Z axis connector

Fig 2: Z axis connector

The large hole (right) will be threaded and two 3mm bolts are to be used to clamp both the rod and motor shaft firm. If they work I’ll upload the .stl’s so that others can use them If they so wish. Otherwise if you are doing a Prusa build I recommend that you go for the Haton coupling design.

The following image shows the current state of play with the mocked up Z Axis.

Fig 3: Current state of play

As you can see Leonard is beginning to look like a RepRap. Rather than do nothing I then decided to have a go at putting together the extruder. All in all the print-head came together quite smoothly, however I did need to clear out the 4 channels that spring load the keeper head.

Fig 4: The print head – gears

Fig 5: Print head heater & extruder

Hopefully tomorrow I will be able to print out the new couplings at work and the build can continue. If not on to the electronics :)

Project Leonard – Z Axis Issues
Posted on November 22, 2011 in Projects by batts