Here's how you can make a butter knife that can handle cold butter straight from the fridge without ripping up your bread or toast.
The original idea is not mine. I spotted it on Kickstarter: https://www.kickstarter.com/projects/1070983896/th...
The project was super-successful, and for good reason; it's a work of pure ingeniousness.
Anyway, with a butter challenge in the offing, I couldn't resist having a crack at making my own. In the end it worked quite well. My fellow Instructablers will certainly be able to improve on the design, but I hope this will at least help inspire someone to have a go.
The only material is some stainless steel. I used the housing of an old submersible bore pump. These things are designed to last so I know it will be good quality stainless steel. The steel is about 1mm thick - you would not want it thinner.
Of course you will also need some tools to cut it out, grind, drill and polish.