I have recreated chair feet for the chairs called OMG and Fourteen Up from the Dutch brand ZUIVER. These are the 42 degree angled feet underneath which you can add vilts to prevent scratching. They fit into a 13MM inner diameter leg/pipe. Base is 25MM wide. The part that goes into the pipe is 12.8MM allowing for easy fit and angle adjustment, they are just snug enough not to fall out. Hope it helps someone, I couldn't find a model online.