Spell-Slot Abacus — print-in-place D&D spell-slot tracker

A print-in-place spell-slot abacus for D&D 5e and most d20 RPGs.

Nine rails are the nine spell levels (1 at the bottom, 9 at the top),

each carrying captive crystal beads. The default bead counts —

4 / 3 / 3 / 3 / 3 / 2 / 2 / 1 / 1 — match a full caster's maximum

slots. **Slide a bead aside to spend a slot; sweep them all back on a

long rest.**

• Prints in one piece, ZERO supports. Rails and bead bores are

•   45° diamonds, so every face self-supports — no bridging over the

•   moving beads. The beads come off the bed already captive on the rail.

• - Tilt-lock carry detent. A low rib at the centre of each rail sits

•   just under the bead bore. Flat on the table the beads slide past it

•   freely; lift or tilt the board and the beads drop onto the rib and

•   can't cross the middle — carry the board without scrambling your

•   count.

• - ~107 × 130 × 8 mm — slips into a dice tray or DM screen pocket.

• - Optional 3-colour (AMS). Frame / beads / numerals as three

•   filaments using the included multi-colour STL: Import → right-click →

•   Split to Parts, assign a colour per part. (The photos show the

•   3-colour print: black frame, amethyst beads, gold numerals.)

Print:

• 0.2 mm layers, 3 walls, 10–15 % infill, PLA/PETG

• - No supports, no brim needed — flat on the bed as exported

• - **Tip: print the coupon(one rail + 2 beads) first** to check the

•   slide fit + rib feel before committing to the full board.

Two files included: the single-colour print-in-place board, and the

3-colour AMS version (split into frame/beads/inlay parts). The OpenSCAD

source is attached — every dimension is parametric (rows, bead counts,

clearances).