# A cassette is five moving parts once the shell comes off

> A compact cassette looks like one sealed object. Drawn with the top shell lifted away, it's two hubs, a felt pad on a spring, three guides and a length of tape, none of it hidden anymore.

August 19, 2026 · https://justog.club/stories/cassette-shell-cutaway

A compact cassette, drawn open. The top shell is lifted clear and set apart from the body, and the
parts underneath it are pulled slightly along one line: both hubs, the tape path, a small felt pad,
two slip sheets, five screws.

Thin leader lines connect each part to where it sits in the closed shell. Nothing is labelled.

Held in a hand, a cassette is one object. Opened like this, it's obviously a small machine that a
lot of people have used without ever once seeing running.

## What are all these separated pieces actually showing?

Every part a cassette needs to move tape past a head without touching it by hand.

The two hubs hold the tape and turn; the slip sheets, thin sheets of low-friction paper behind the
tape pack, stop the reels from grabbing at each other unevenly as they spin; the guides keep the
tape running in a straight, repeatable line past the opening in the shell. None of it does anything
until a player's own motor and head come into contact with the exposed section at the front edge.

## What is the pressure pad, and why does it get its own space in the drawing?

A small pad of felt on a spring, and it's the part that fails first.

The pad's whole job is holding the tape flat against the player's head as it passes, which sounds
trivial until the felt wears thin or the spring loses tension — at which point the tape lifts
fractionally off the head and the sound goes dull before anything else in the mechanism shows a
sign of wear. Most people who've owned cassettes have never opened one far enough to find it,
which is exactly why it's drawn here rather than left out.

## Why draw it exploded rather than as a flat diagram?

Because a flat diagram shows where parts are; an exploded one shows that they're separate.

Laid out along one axis with gaps between them, each piece reads as an individual object rather
than a printed illustration of a shape everyone already recognises. It's the same choice
[a reel-to-reel deck's two spools](/stories/reel-to-reel-two-spools) makes by putting a full
and an empty reel side by side instead of drawing the machine as a whole — the mechanism is the
subject, not the silhouette.

## Can a real cassette brand or shell design go on the shirt?

The shell's shape and layout are a generic mechanism. A specific manufacturer's casing, labelling
and cover card artwork are a different matter.

Every cassette shell of this type shares the same hubs, guide posts and screw layout because they
all have to fit the same players — that arrangement belongs to nobody. What a specific maker owns
is their own printed label design and case colour, which is licensable the ordinary way any
manufacturer's own product design is. Left unlabelled, as this one is, the print stays the
mechanism rather than one company's packaging.

## Does this only work for music?

No — any cassette, including ones that carried nothing but voice or data, opens the same way.

Answering machines, dictation recorders and early home computers all used this exact shell with the
same hubs and pad, holding a different kind of recording behind the same five screws. The print
doesn't specify which one it was, and it doesn't need to, because the mechanism inside is identical
either way.

## Isn't printing an old format on a shirt just nostalgia?

The mechanism doesn't need the format to still be current to be worth drawing.

What's on the shirt is a working explanation of five parts and how tape moves between them, which
is true regardless of whether cassettes are being manufactured this year or not — the same way [a
valve amplifier's own glowing insides](/stories/valve-glowing-amp-guts) are worth drawing
whether or not anyone still argues about them.

## Does it print well?

Yes — an exploded view with thin leader lines is built for flat colour and clean separation.

Charcoal for the shell keeps the cutaway readable as one object pulled apart rather than several
unrelated shapes; cream for the tape and hubs and a single yellow for the pressure pad keep the one
part most people have never seen singled out without adding a third ink just for it.

## How do I get one made?

Describe the cassette at [JustOG](/) — how far apart to pull the shell, and which parts to leave
in or out. Pick a direction, drag the crop frame, see it composited on the real garment, and it's
made to order and shipped.

Designs other people have published are in the [shop](/shop).

Five screws removed, and a shape everybody has held turns out to be a shape almost nobody has seen.