Oh Mr Max – you’ve found the most beautiful Steampunk things!  Above is one of five Adding Machines created by Mr Andy Aaron at Aaron Adding Machines – and they are perfectly stunning.  From the site itself:

“By means of an Aaron Adding Machine, a person entirely ignorant of Arithmetic, may perform tabulations such as Addition, Subtraction, Multiplication and Division, more correctly, and in much shorter time, than the most experienced Mathematician could calculate it.”

There are portholes, operational keys, brass numbers, engraved numbers, scorched numbers, pull handles, knife switches, side winding handles and more – they’re all so utterly perfect that I can barely stand it!  Worse still, I can imagine that the means for constructing something like this is within the grasp of many (though it pains me to think that they are ‘merely’ calculator casemods) – but it is Mr Aaron who was struck with the inspiration to make such ravishingly Steampunk variants.  One of these, for my desk, and I’d be looking for any excuse to further abandon my mental arithmetic!