Button Repair on OBH Nordica Coffee Grinder

Are you lucky to own one of these coffee grinders? You should especially be careful with the amount of force you press the button with. They have a flaw with brittle plastic buttons. I became aware of this about 10 years ago when my parent's coffee grinder suffered the same problem. Back then I solved the problem with a light switch on the power cable and wiring around the electronic control circuit. Now after buying one many years later, they still haven't fixed the problem. So now with a little bit of 3d modeling and printing knowledge, I wanted to try a different approach.

For this fix, you will need:

• Access to a 3d-printer
• Small piece of breadboard/prototype board (or other thin board with mechanical strength)
• Super glue
• Isopropanol/alcohol
• Screwdriver set

This can be kind of tricky to disassemble the first time. Try to pry the plastic parts gently with a flat screwdriver.

Every step in this guide should be done with the power cord disconnected.

1. Dismantle the centerpiece in the grinder chamber. Should be marked with a direction, and pulled out easily.
2. Dismantle the adjuster on the side with a flat screwdriver. (not the one on the front panel)
3. Orienting the coffee grinder so you see the bottom. Put the flat screwdriver gently in the middle of the two plastic pieces forming the sidewalls. As shown in the picture. Work your way around while trying to lift it upwards.

This video by alexis c show the whole process:

Many signs in the design show that the arm holding the button in a stationary position is too brittle. So I wanted to strengthen its flexibility with a piece of prototype board. It's thin glass fiber that has a hard time snapping. Dimension for this board is: 12mm long, 3mm wide, 1mm thick.

I reused all the acrylic parts. The bigger piece touching the button comes off easily. The part inside the button is glued in place. After a little bit of isopropanol and prying with the flat screwdriver, it came loose.

For attaching acrylic parts to the 3d printed parts I used super glue. Just a small amount is necessary though. That makes it easier to disassemble and improve the design in the future.

Print settings:

• 0,4 nozzle
• 2 walls
• 4 top/bottom
• 25% infill
• Support (touching build plate)

Print with the flat side down.

I think this design can be improved by using glass fiber for the whole length including the screw-hole. I think it's easily modifiable by removing a little bit of plastic around the screw. My solution has been working for months showing no form of weakness. So this improvement I will spare for later.