Drive Arbor thickness
  • Hello people.

    I recently received my Septimus kit and I am in the process of putting it together. I am currently working on the drive arbor and I am wondering if I am doing something wrong since the thickness of the assembly does not match the thickness mentioned in the instructions or even the theoretical thickness according to the plywood sheet thickness.

    For example my click wheel assembly measures 43mm (photo attachment 1). Theoretically it should measure around 38mm since it consists of 5x4mm pieces and 3x6mm pieces.

    My arbor is 59mm long and when inserted in the whole assembly (click wheel and drive wheel) it protrudes just by 7 mm (photo attachment 2). This means that the thickness of the assembly is 52mm instead of 46 as mentioned in the instructions.

    Therefore I need to sand away around 6mm which is the thickness of the top spacer (3B). Would that be acceptable? In the instructions David mentions that the plywood tends to be a bit thicker than stated, but I think that in my case it's too much. Should I just try to completely remove spacer 3B? Am I doing something wrong?

    Thank you in advance,
    804 x 1000 - 231K
    1000 x 759 - 190K
  • As mentioned in the instructions plywood can vary in thickness, and depending upon batch it can be quite substantial.
    This was the reason why I added the spacer (3B), remove the spacer totally to reduce the stack thickness, check the frame gap and if the stack still does not fit with a 1.5/2mm gap then shave off a sliver from the front of the stack (Barrel spacer 7A) and the back (Spacer 1A).
    Do not worry you are doing nothing wrong, it is just that when you work with wood, even plywood, you have to compensate for the fact that mother nature knows nothing of millimetres.