Monday, March 22, 2010

MDF Secured

Made a little more progress this weekend on the RepStrap. Attached most of the MDF that will be on the frame, and i think the proof of concept build surface is going to work just fine.

This is the underside of my y-axis/build surface. It is basically just bearing supporting the carriage like a normal 4 wheeled cart. I am using 2 bearings per corner, but this could probably be reduced to 1.

The bearings i used are smaller than the fixit blocks so they were easy to mount. the support for side-to-side tray motion is provided by the slight lip of the fixit block pressed against the square rail, which you can make out in the 1st picture. So far this seems to work, there is very little wiggle in the bed, and it moved freely forward and backward. My hope is once the herringbone rack is printed and installed the tray will be further stabilized, and the tight tolerances will be less important.

Lastly, I managed to install the bottom tray that will mount the z-axis and potentially the stepper for the y-axis. I notched the MDF to allow the gear/pulley drive to clear the threaded rod on the bottom of the machine.


  1. Your now being followed by me. I like the pvc corners plus the fixit blocks. Saw your comment on GilesBathgate's site.

    Question? What's the square tubing going to be used for?

    Looks like the mdf will be strong enough for the x-axis even with the notch. Maybe no notch if the corner pvc had been a little bigger and mount the mdf under? Second guessing here.


  2. What do the bearings ride on? The square tube? What will keep the platform riding square to the frame?

  3. Just had to read further....

  4. to clarify, the bottom board is not an axis. it holds the bottom of the gears/motors for the z-axis.

    and you are right, if I had used larger pvc ends or thinner MDF i could have eliminated the notch. alternatively, i could have worked around the threaded rod, but notching the board seemed like the cleanest solution.