Two digit abacus

The Abacus consists of:
- top bar (Shell_T)
- central bar (Shell_C)
- lower bar (Shell_B)
- left (Shell_L) and right (Shell_R) bars
- counting beads - two upper (Bead_t2) and eight lower (Bead_t1).
After printing you have to glue bead halfs together.
You also need two studs 2x75 mm. Initially I tried to print them but then decided to use 2 mm steel. It can be made both from steel whire, plastic and wood. I prefer steel :)
All the joints are adjusted for 3D printing.
This abacus parts can be easily assembled/disassembled and sections can be stacked together.