Like most people, sin and cos aren’t math functions I use every day. So calculating a cone, slicing it in two places, plotting the curves, factoring in leather thickness, and making sure the sleeve didn’t go too high or low on a coffee cup or travel mug was quite an experience. Then multiply that work x the different sizes of coffee cups on the market.
I later created a custom Excel spreadsheet that prompts you for the cup dimensions and leather thickness, then performs the calculations for you.
This leather coffee cup sleeve is constructed of full grain leather up-cycled from a 50+ year old farm machine drive belt. The sleeve is hand-sewn with heavy duty wax-coated polyester thread.
Due to the rarity of the material, each coffee sleeve is bespoke and custom-made to order.