From the Loftsmith Workshop

Cat treat dispenser caps for toilet roll tubes, 36-52 mm

Turns a spare toilet roll tube into a puzzle feeder for your cat. A cap goes in each end, and the treats come out through small holes in the ribbed rim as the tube gets rolled and batted about. Set the tube width and treat size to match yours.

4 parts · 58 g · 172 × 56 × 56 mm

by Loftsmith Workshop

Cardboard-coloured tube with a ribbed yellow cap at each end, teal rings and holes in the rims
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No adjustable sizes

Ask for the sizes you want to tweak, e.g. “make the width adjustable”.

Change it in the Studio

Parts

  • cap 1 · PETG · Outer end face down, fingers pointing up

    Prints as one object with shutter ring 1 (print-in-place). About 56 x 56 x 56 mm and about 19 g at the defaults. Has 8 flexing fingers that grip the tube.

  • shutter ring 1 · PETG · Prints in place around cap 1, on the bed

    Held captive on the cap's V-ridge. About 10 g. Free it with a firm twist after printing.

  • cap 2 · PETG · Outer end face down, fingers pointing up

    Same as cap 1; prints as one object with shutter ring 2.

  • shutter ring 2 · PETG · Prints in place around cap 2, on the bed

    Same as shutter ring 1.

Print settings

Layer height
0.2 mm
Walls
2 walls (the page default: about 60 g and 1 h 50 min for both caps). For tougher caps, use 3 walls: about 84 g and 2 h 32 min.
Infill
15%
Supports
None. The holes have teardrop tops, and the rim and the ring's capture ridge use 45-degree slopes.
Notes
PETG, because it is tougher than PLA and survives batting and drops better. Each cap and its ring print together as one object, so keep them together in the slicer. Do not use a brim, because a brim can fuse the ring to the cap. If the ring will not free up, increase the Ring guide gap slider (choos

Hardware

  • Empty cardboard toilet-roll or kitchen-roll tube · Measure the inside diameter and set the Tube inside diameter slider (36-52 mm). Toilet-roll cores are usually about 40 mm inside.
  • Dry cat treats or kibble · Set the Treat size slider to the largest treat; each hole is the treat size plus 3 mm.

Assembly

  1. Print both caps outer face down, each with its ring in place. Do not use a brim.
  2. Hold each cap and twist its ring firmly until it turns all the way round.
  3. Turn each ring so its windows line up with the cap's holes (open), sit halfway over them (harder), or sit between them (shut).
  4. Fill the tube with treats and push one cap into each end, fingers first, until the tube end sits against the rim.
  5. Roll it on the floor. Treats drop out of the open holes as it turns. To refill, pull one cap out.

Good to know

  • Supervise your cat while it plays and remove a cap once it is chewed. PETG is tough but not chew-proof, and the caps are not certified food-safe.
  • The grip forces are design estimates, not measurements: about 90 N to pull a cap out and 36 N to push it in at the defaults, assuming friction of 0.3 on cardboard. A soft or squashed tube holds less. Measure your tube and adjust the Tube inside diameter slider if the fit is loose or too tight.
  • With large treats in a small tube, the design prints fewer holes than you ask for, so the ring can still shut every hole fully. The 'Ring shuts every hole' check states the limit for your tube: in the default 40 mm tube, 15 mm treats allow up to 3 holes.
  • The ring has no click stops; only its fit holds the setting. It sits 2.5 mm inside the rolling rim, so a smooth floor does not turn it, but thick carpet or hard batting can move it and change the setting.
  • The engine checked that the ring clears the cap in 24 rigid positions, that it is captive and that it shuts the holes. How easily it frees up and how stiffly it turns depend on your printer and need a test print.
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