Overview

Build a quiet, stable, paw-safe cat exercise wheel using plywood rings and urethane roller wheels (skate/longboard wheels). This plan is written like a project/homework handout: goals, constraints, cut list, steps, checkpoints, and test criteria.

Target wheel size (recommended):

  • Outer diameter: 48 in (4 ft)
  • Track width (running lane): 11–12 in
  • Overall base footprint: ~24 in deep × 44 in wide
  • Recommended cat size: most adult cats (8–18 lb)

Why 48 in? Larger diameter = gentler curve, more comfortable gait, and less strain.

Safety requirements

  1. No pinch points: Cat paws must not reach the rollers. Use side guards and keep roller gaps small.
  2. Stable base: Must not tip when a cat enters/exits.
  3. Smooth track: No staples, protruding screws, sharp edges, or looped carpet.
  4. Non-toxic materials: Use low-VOC wood glue and finishes once cured.
  5. Noise control: Urethane wheels + aligned rollers + balanced wheel.

Supervision: Always supervise training and early use. Never force the cat to run.

Bill of materials

Wood

  • (2) 4×8 sheets 3/4 in plywood (cabinet grade preferred)
  • (1) 4×8 sheet 1/4 in plywood (track skin)
  • (2) 1×6 boards, 48 in long (base rails)
  • (1) 1×4 board, 48 in long (cross brace)

Motion parts (roller method — recommended)

  • (8) inline skate / longboard wheels, 60–70 mm urethane (with bearings)
  • (8) 5/16 in bolts, 2 in long (or length that fits your wheel thickness + washers)
  • (16) 5/16 in washers
  • (8) 5/16 in lock nuts (nyloc)
  • (Optional) (8) 5/16 in fender washers (spreads load on plywood)

Fasteners & adhesives

  • Wood screws: #8 × 1-1/4 in (1 box)
  • Wood glue (PVA)
  • Construction adhesive or contact cement (water-based preferred) for track covering
  • Wood filler

Track surface

Choose ONE:

  • EVA foam sheets (best: quiet, grippy, paw-friendly)
  • Cork roll (quiet, durable)
  • Low-pile carpet (avoid loops: claws can snag)

Finish (optional)

  • Water-based polyurethane or hardwax oil (fully cured before use)

Tools required

  • Jigsaw (or bandsaw)
  • Drill/driver + drill bits (1/8 in pilot; 5/16 in for bolts)
  • Router with circle-cutting jig (strongly recommended) or DIY trammel jig
  • Measuring tape, square, pencil
  • Clamps (4+ helpful)
  • Sandpaper (80/120/220) or orbital sander
  • Safety glasses + hearing protection

Design specs and key dimensions

Ring dimensions

  • Outer ring radius: 24 in (48 in diameter)
  • Inner ring radius: 18 in (36 in diameter)
  • Ring “rim” thickness: 6 in (this forms the sidewall)

You will make two identical rings from 3/4 in plywood.

Track width and skin

  • Track width between rings: 11–12 in
  • Track skin: 1/4 in plywood strips that wrap around the rings to form the running surface.

Roller placement

  • Use 4 rollers per side (8 total), mounted on the base uprights.
  • Aim for rollers contacting the wheel at roughly “2 o’clock, 4 o’clock, 8 o’clock, 10 o’clock” positions.
  • Keep the wheel centered with small side clearances (1/8–1/4 in).

Cut list

From 3/4 in plywood

  • (2) Outer rings: 48 in diameter
  • (2) Inner cutouts: 36 in diameter (these are waste/optional scrap pieces)
  • (4) Uprights: 18 in tall × 6 in wide (or cut as you like; must hold roller bolts)
  • (2) Side guards: 48 in long arcs or straight panels (optional but recommended)

From 1/4 in plywood (track skin)

  • (6–8) strips: 4 in wide × 48 in long
    (quantity depends on exact width; you can also do fewer, wider strips if your plywood bends well)

From 1×6 lumber (base rails)

  • (2) rails: 44 in long
  • (2) feet: 22–24 in long (front/back)

From 1×4 lumber (cross brace)

  • (1) brace: 44 in long

Step-by-step build

Step 1 — Make a circle-cutting jig

If you have a router:

  1. Create a simple trammel jig: a straight strip of plywood with a pivot hole at one end and router mount at the other.
  2. Mark pivot point and radius (24 in for outer; 18 in for inner).

If you do not have a router:

  • Use a nail-and-string compass to draw circles and cut carefully with a jigsaw. Sand to smooth.

Checkpoint: Your two rings must match within ~1/8 in.

Step 2 — Cut the rings

  1. Mark and cut two 48 in circles (outer).
  2. Mark and cut 36 in circles inside them (inner cutout).

Tip: Cut the inner circle first to keep the sheet stable.

Checkpoint: Stack rings: edges should align closely. Sand flush where needed.

Step 3 — Build the base frame

  1. Lay out the (2) 44 in rails parallel, ~16–18 in apart.
  2. Attach front/back feet (22–24 in) to form a rigid rectangle.
  3. Add the 1×4 cross brace across the top where uprights will mount.

Checkpoint: Base should not rack (push corner-to-corner; it should feel rigid).

Step 4 — Cut and mount uprights

  1. Cut (4) uprights from 3/4 in plywood: ~18 in tall × 6 in wide.
  2. Mount two uprights per side on the base rails (left pair and right pair).
  3. Ensure uprights are square and parallel.

Checkpoint: Distance between left uprights equals distance between right uprights.

Step 5 — Install the rollers

  1. On each upright, mark two roller locations (upper and lower).
  2. Drill 5/16 in bolt holes straight and square.
  3. Install wheel + washers + locknut so the roller spins freely.

Alignment rule: The four rollers on each side must form a smooth “cradle” that supports the wheel evenly.

Checkpoint: Spin each roller by hand: no wobble, no rubbing.

Step 6 — Assemble the wheel (rings + track skin)

  1. Cut 1/4 in plywood strips for the track skin.
  2. Dry-fit strips around the ring edges to confirm bend.
  3. Glue and screw strips to the rings to form a rigid “drum”:
    • Space screws every ~4–6 in
    • Countersink slightly so heads sit below the surface
  4. Keep track edges flush; sand transitions smooth.

Checkpoint: Wheel is round, rigid, and doesn’t “egg” when you press on it.

Step 7 — Add the running surface

  1. Sand the inside track smooth (120–220 grit).
  2. Apply EVA foam / cork / carpet:
    • Use contact cement per instructions
    • Avoid seams that create bumps; stagger seams if using multiple pieces
  3. Trim edges cleanly.

Checkpoint: Run your hand along the track: no snags.

Step 8 — Fit wheel onto rollers and center it

  1. Lift wheel onto the roller sets.
  2. Check clearances:
    • Side gap between wheel and uprights/guards: 1/8–1/4 in
  3. If the wheel walks side-to-side, add:
    • Side guards
    • Or thin UHMW/nylon “guide blocks” that lightly touch the ring edge

Checkpoint: Wheel spins smoothly with a light push and does not rub.

Step 9 — Add side guards (highly recommended)

Guards prevent paws from reaching rollers and reduce derailment. Options:

  • Arc guards: thin plywood arcs that follow the wheel edge
  • Straight panels: mounted near uprights to block access to rollers

Checkpoint: Cat cannot reach roller wheels from inside the track.

Step 10 — Finish and final safety inspection

  1. Fill holes and sand.
  2. Apply finish only on exterior surfaces if you want to keep the inside as grippy as possible.
  3. Let finish fully cure (follow product cure time).

Final checks:

  • No sharp edges
  • All screws flush
  • Roller bolts tight, rollers spin
  • Wheel spins with light force and coasts

Testing and grading rubric (homework style)

Functional tests

  • Spin test: Wheel coasts at least 5–10 seconds from a gentle push.
  • Noise test: No squeaks; no scraping.
  • Stability test: Push sideways on the top rim: base does not tip.
  • Safety test: No access to rollers from inside the wheel.

Quality targets

  • Rings match within 1/8 in
  • Track seams smooth to the touch
  • Roller alignment: wheel does not wobble or drift excessively

Cat training plan

  1. Day 1–2: Leave wheel stationary. Place treats/toys near and inside it.
  2. Day 3–5: Encourage short steps by moving a wand toy slowly.
  3. Day 6+: Reward voluntary running. Keep sessions short (30–60 seconds).

Do not: spin the wheel fast to “make” them run.

Troubleshooting

Wheel wobbles

  • Rings not identical → sand edges flush as a pair.
  • Track skin pulling unevenly → add more screws, clamp while gluing.

Wheel drifts sideways

  • Roller heights not symmetric → re-measure and shim uprights.
  • Add side guards or guide blocks.

Loud rumble

  • Replace hard wheels with softer urethane.
  • Ensure bolts aren’t overtightened (rollers must spin freely).
  • Add thin rubber pads under the base feet.

Cat won’t use it

  • Lower pressure: treats + play near it.
  • Try different surface (some cats dislike carpet texture).

Optional upgrades

  • Speed limiter: light felt pad touching the rim to add gentle drag
  • Odor control: removable track liner for cleaning
  • Decor: paint exterior, add nameplate
  • Base storage: shelf for toys/treats

Estimated cost and time

  • Materials: $120–$180 typical (depends on plywood and surface)
  • Build time: 6–10 hours including sanding and fitting (not including finish cure time)

Notes for documentation photos

If you’re turning this in as a class project, photograph:

  1. Ring cutout step
  2. Roller installation close-up
  3. Track skin attachment
  4. Finished wheel and safety guards
  5. Cat using wheel (optional, but fun)