Q-tip Cup — Fluted Cylinder with Snap-Fit Lid

A fluted Q-tip cup with a friction-snap lid. Holds about **250

standard 75 mm cotton swabs** in its Ø65 × 58 mm inner cavity.

Inspired by a Doric column — 24 shallow concave vertical flutes

wrap the cup wall; the lid is a flat disc topped with a faceted

octagonal "gem" dome that doubles as the lift handle.

Closure (snap-fit, re-openable, audible click). The lid has a

downward plug that fits inside the cup mouth with a 0.10 mm

diametral slip. A small annular bead 3 mm up the plug clicks into

a matching groove just below the cup rim. Four axial slits cut the

plug into four 90° petals that flex inward to let the bead pass on

close / open. The bead's lower face is chamfered at 30° from

vertical so it self-engages and prints cleanly on the lead-in

overhang.

The lid disc sits flush on the cup rim when seated.

Dimensions

| Part   | Outer Ø | Height       | Notes                          |

|--------|---------|--------------|--------------------------------|

| Cup    | 69 mm   | 60 mm        | inner Ø 65, wall 2.0 mm        |

| Lid    | 69 mm   | 2.5 + 7 disc | plug Ø ~64.9, dome height 7 mm |

Print

• cup — open end UP on the bed. Floor first, walls climb up.

•   No supports.

• - lid — plug DOWN on the bed (the lead-in chamfer face on

•   bed). The four slits print as clean vertical voids. The bead's

•   lower flank is the only overhang and is angled at ~30°.

0.2 mm layers, 3 walls, 15 % infill. Any PLA / PETG. Two parts

print in ~2.5 h combined on a Bambu P2S.

Tuning the snap. The bead's radial interference is 0.30 mm

(0.60 mm diametral). If V1 won't seat → drop bead_radialto

0.20. If V1 comes off too easily → raise to 0.40. Both knobs

live at the top of qtip_cup.scad.

Parametric. Edit the variables in the SCAD to retune the cup

diameter, height, flute count, lid dome size, snap interference,

and slot count. Everything downstream (groove position, bead

geometry, plug Ø) is derived so re-rendering with a different

cup_odor cup_hjust works.

Photo gallery shows the printed cup + lid (yellow PLA): one shot

of the lid set down next to the open cup so you can see the

plug + slits + bead, and one of the lid snapped on showing the

faceted gem dome.