I also got my hands on a Tentaku calculator. It’s kind of just a novelty thing but I’ve wanted a desktop calculator for a while.
I mill maxed it and 3d printed a plate and backplate for it to replace the 2mm acrylic crappy ones that came with. Put some lubed Boba U4s in and threw on some Sixes. I may swap it with Nines I think.
Moar pics n stuff
^Mill maxed with 7305s as I always do. Cleaned with 91% IPA and a rag.
^Modeled up just a simple plate and backplate. Original plates were 2mm clear acrylic–switches don’t clip in fully and the backplate kept flexing and hitting the PCB. The acrylic backplate was also cut wrong so it was shifted 2-3mm too far up, so I centered it, added a spine on the underside to for rigidity and to standoff from the PCB, and holes for the 10mm bump-on feet. I guess you’re supposed to just slap on the feet wherever on the acrylic plate which is silly.
I always forget to take pictures of the actual pieces until after assembly
Overall for the price I think it was a good buy, but the acrylic that came with was pretty useless and ruins it IMO. The assembly could have been more robust (the standoffs are plastic), the PCB had rosin everywhere before I soldered, and if you input numbers too fast it will glitch out.
That said, I still like it and the build was fun.
Here’s the plate files in case anyone else gets/has one of these: Tentaku Mechanical Calculator plate and backplate by skwrl - Thingiverse
Thanks for lookin’ 
EDIT: Swappped Sixes for Nines and Boba U4s for L+F Gat Inks
