Maslow CNC 12 o'clock level

One of the steps during the setup/calibration of the Maslow CNC is to set the sprockets so that one of the "teeth" is set to the 12 o'clock position. This is a tool to help set that more accurately. For more information on how offset in your 12 o'clock position can affect accuracy, see this forum post from c0depr1sm: Set your 12 o’clock position with a level… because

It uses a bubble level like this: 10 Pcs Cylindrical Plastic Bubble Spirit Level Vials, 8*35mm which are normally used for photography/cameras.

Just glue the bubble level into the slot and then slide it on top of the sprocket.

Also note that you want to set the sprocket to 12 o'clock in relation to your top beam (that the two motors are mounted to). So make sure your top beam is also level when using this tool.