Oil Clock

A machine's service is not counted in weeks. The oil change comes due after so many running hours, and the only person who knows how many hours a generator, tube well, pump or compressor has actually run is whoever remembers to look at the meter and write the figure somewhere. That figure usually lands in a diary, one number under another, and nobody ever subtracts one day from the next. So the service arrives when the machine starts sounding wrong.

Oil Clock is that diary with the arithmetic done. Each machine sits on the rack as an hourglass: the sand still in the top is the hours left before its next service, the sand below is the hours it has run since the last one, and the machines are ordered so the one nearest its service is the first thing you see. When a machine goes past the figure you set, its glass spills out of the base and keeps counting the overrun until somebody records the work.

Logging a day takes about ten seconds. The entry screen is the meter itself — a register of digit cells filled from a keypad — and as the digits land, the hours the machine ran appear underneath, worked out as the difference from the last reading you gave. Machines with no meter fitted are timed by hand instead, in hours and minutes. If a day is missed, Oil Clock says the day has no reading rather than pretending the machine stood still, and a machine that genuinely did not run is recorded as idle, which is a different fact and is treated as one.

Meters do awkward things, and this is where a paper diary quietly goes wrong. A five or six digit meter eventually wraps back to zero, and a meter that fails is replaced with one starting from nothing. Either way tomorrow's reading is smaller than today's. Oil Clock will not guess: it stops and asks whether the meter rolled over, was replaced, or was typed wrongly, then keeps the machine's lifetime hours intact across the change so no service interval is disturbed. Recording a service asks at what hours figure the work was actually done, so a job you enter three days late still counts from where it happened.

The review screen gathers the fortnight: hours run per day across every machine, what has not been logged today, how many days have no reading behind them at all, how hard each machine is really working in hours a day, what has gone past its hours, and what falls due next — with a projected date built from that machine's own recorded average, and an honest refusal to project one until there are enough days to justify it.

Every interval in Oil Clock is a figure you typed, taken from your machine's own book or your own practice. The app suggests none and ships with none, prescribes no schedule, and knows nothing about any particular engine. It makes no claim that a machine is safe, serviceable, under warranty, or fit for use — it records what you entered and counts. There is no money anywhere in it: no costs, no prices, no charges for parts or labour. Nothing is uploaded, there is nothing to sign into, and the record lives on your phone.