The bottle cutter was designed to propose a precise template to build it.

Building the cutter

You will need 

• a scrap 10cm long square pipe 3x3cm section
• 2 x 7 cm long 8mm diam threaded rod
• 1 x 3 cm long 8mm diam threaded rod
• 2 x 608Z roller bearings
• 5 x 8mm nuts

Drill the following holes into the pipe

Drill them so that you can tap them at 8mm  on the top face only.

You can use the 3d printable gauge to help positionning the holes and keeping the drill perpendicular.

The long rods go down to the other side and can be soldered to fix them. If you prefer you can make them longer and use nuts to fix on the bottom side.

Then, with a metal saw, cut a 8mm notch into the small "finger"

If needed you file or grind the top part of the threads so that the finger will not touch the bottom roller bearing (the one on the left).

This "finger" is positionned at the correct height and then blocked by the nut.

The rollers bearings will be first sharpened and then tuned so that :

• the bottom of the notch in the finger and the top of the lowest roller are at the exact wanted height of the ribbon. I do cut my ribbons at 8.5mm.

• the two bearings must turn when rotating only one of them (as if they where gears). You can achieve this when fixing the top bearing with the nuts.

Sharpening the roller bearings

 See this log