The story:

My grandfather challenged me to design this after a visit to a local elderly (89 years strong) business woman. During his visit to her shop she remarked she is having an issue opening pop bottles. He immediately challenged me to help her out as he has been doing business with the family for some time. I showed him some designs I found and he wasn't satisfied, he wanted it to be as small as usably possible.

The model:

This model uses a left hand tapered thread, meaning the more it is screwed onto the cap the tighter it is to increase variety of soda bottle caps it can fit on. All edges are rounded for comfort and safety. A hole is cut into one corner to allow some sort of cordage to be added for hanging/storage. I have tested with Pepse , Coke, and Dr Pepper products. The fit on pepsi products seems to be more snug and may require a slight scaling up of the model (like 1-2%) in the xy directions.

Print instructions:

I used PLA and it printed fine at 0.2mm layer height. I also opted for 3 walls for some additional strength as most force will be along the layer lines. Print flat with opening up, model should already be oriented as such.No supports needed.

Using the model:

To use the bottle opener, place on the plastic cap of your favorite bottled beverage(some caps won't work such as store brand water), and apply a steady pressure down as you twist the cap off as you normally would. Once the threads bite into the bottle, the cap will not fall out. You must screw the cap back on to the bottle to remove the tool. At this point the tool should hopefully no longer be needed.

Video explanation: https://www.tiktok.com/t/ZTRTTHkff/

Update 4/25/23. Added Version 5.

Version 5 has a wider mouth for more compatibility without the need to adjust scale.