Quarters: the fuel

This is where our first real bug lived, so it gets its own chapter. The machine doesn't just accept a quarter — it measures it, stacks it, slides it, and counts it, all by geometry. The quarter is a precision part.

Metaphor. Fuel quality. Dan doesn't run gunked-up gas through a rebuilt carburetor, and he doesn't run it on something with the wrong octane either.

5.1 Gunky quarters

Old circulated quarters carry grease, pocket lint, soda, and whatever else. Every sticky quarter that goes through leaves a little of that on the escalator, the tube walls, and — worst — the payout slides, which are supposed to run dry with almost no clearance. Enough residue and the slides drag, meter short, or stick forward. Sticking forward means the reset doesn't complete. That's a missing last click.

Fix: wash the quarters. Warm water, a little dish soap, rinse, dry completely. Don't put damp coins in. Then clean the slides and tube dry (solvent on a rag, no oil) — the residue that's already in there doesn't leave on its own.

5.2 Sharp new quarters

Brand-new quarters have a crisp reeded edge and a sharp rim. The coin path was cut in 1937 for quarters that had been in pockets for a while — slightly softened edges that glide. A mint-sharp edge can catch in the escalator, hang up in the tube, or bind in the slides. It looks like a random jam and it isn't.

Fix: feed it worn, circulated quarters. Keep a jar of "machine quarters" that have been through it and behave. Don't feed it a fresh roll from the bank.

5.3 Foreign objects

A wrong-size coin, a token, or a bent quarter in the tube stops the whole till. If pays are short and the slides look clean, look up the tube.

5.4 The rule

Clean, worn, dry quarters. If the machine is jamming and you haven't checked the quarters, you haven't started.