I have finished building the Z axis roller that is mounted on the other Z axis rail. I really liked the axes design that Ed has used for mendel. I can imagine that if the Z Axis rails were not exactly parallel, and I had used two identical skates, then there would be the possibility that the skates would jam either at the top or bottom of the axes.
My design includes a 1/2″ x 1/8″ aluminium bar that is made by cutting an edge off a length of aluminium angle that I have used before.
Here are a few extra drawings of the parts shown in the photo from the post I did a few weeks ago.
The chassis is made from 12mm thick mdf. I chose 12mm thick mdf so that it would be the same width as the original parts that I made from 12mm thick timber, as such someone wanting to make both those parts and the chassis on a cnc router machine could make it from one sheet. I am not really sure why I chose 12mm thick for corner parts, it just seemed like a good thickness at the time.
I think its important to give as much detail as possible so that anyone else wanting to make one could do so, and so that people can make improvements. Well, I suppose that’s the whole point of open source.
As usual the drawings are here
I have built the first of the Z skates for OverlapStrap.They can be tightened using the 4 M4x40 bolts, and when tightened just right they run very smoothly. I haven’t had a chance to upload any drawings of the parts that make it up yet.
This image gives you an idea of angles at which the bearings are arranged.
I have tried to make the chassis constrained the same way as it is in the original mendel, however I am relying on gravity to hold the chassis down so I only need 6 bearings in total for the chassis. Below is a picture of the chassis mounted to the OverlapStrap frame.
The main reason my plans for this repstrap deviate from the work being done by bodgeit was because he uses 606 bearings. I wanted to use the M4 bearings that are part of the Mendel Bill of materials. Instead I have made these skates inspired by those used in the build your cnc project.
The M4 bearings are mounted on 1/2″ x 1/2″ x 1/8″ Aluminium Equal Angle which I picked up from eBay
As usual the dxf files can be found here
A couple more drawings for the Z-Rail Mounts.
The upper mount
The lower mount
All Files can be downloaded here
So far all I have done is built the frame with Y and Z axes. All bars are the same lengths as in the original mendel. The wooden parts are made from 12mm x 32mm planed smooth timber.
The dimensions for the corner pieces are shown in the following drawing.
I will be providing all files in dxf format. You can download the above drawing here