Aristo

Aristo M76 S

Dennett & Pape, well-known slide rule makers under the Aristo label, switched over to selling calculators in the mid 1970s. They made just a few generations of designs, the first ones being narrow, tall and thin. This one is from the second generation, where they made them wider in acknowledgement that they needed more keys and functions.

I think this calculator has great eye appeal. And it feels great in the hand: less than 1/2" thick, solidly built, nice heft. Yet, it's kind of a pain to use. First, the cover fits so tightly that I'm afraid of snapping something every time I remove it either off the front (where it protects the entire face really well) or off the back, onto which it snaps when you're using the calculator.

Then too, everything interesting is a secondary function, which means you have to use that F key a lot. It's especially irritating that all the memory functions are secondary, and they're not even arranged together. Wouldn't it have made more sense to make x<->y a secondary function and put x->M on that key, with M->x as its secondary? x<->y isn't all that useful, especially because x and y are the same thing after every completed operation. To each his own, but as much as I like the look, shape and feel of this calculator, only the 4-banger functions are convenient to use.

The M76S uses NiCad batteries which can be recharged from a 3V center negative AC adapter. A sibling, the M76, used replaceable batteries. Interestingly, the NiCads are neither hardwired nor supplied as a sealed package. Instead they're just 2 separate cells in your typical battery compartment. Thus, you're free to use disposable batteries instead, I guess. If you use NiCads, you can charge them and operate the calculator with a 3V center negative AC adapter. If you use disposables you should remove them before using an adapter. (Here you see me powering the calculator from an adapter because I've removed the NiCads to avoid corrosion.)

Sold in 2018 for $80.