Welcome. I'm Ernest, and I fix old clocks in my basement for the fun of it. I spent thirty-four years making dies and fixtures in a machine shop, and when I retired in 1994 my wife, Dorothy, said I needed something to do with my hands or I'd start "improving" the kitchen. A neighbor gave me a dead mantel clock, I took it apart on the ping-pong table, and that was that. I've since brought back something over forty clocks, most of them the ordinary American spring-driven kind that sat on every kitchen shelf and parlor mantel between about 1880 and 1940.

I'm not a professional and I don't take in work for money. What I can offer is what I've learned by doing it slowly and carefully, plus the mistakes so you can skip them. If you've inherited Grandma's clock and it won't run, most of what's wrong is probably on this page. And if it turns out to be beyond you, I'll say so, because there is no shame in taking a good clock to a good clockmaker. There is some shame in ruining one.

A word first: the two things that damage more old clocks than time ever did are household oil and impatience. Please read the oiling section before you touch a can of anything.

Every mechanical clock on my bench has the same four parts, whatever the case looks like on the outside.

1. The power. Either a coiled mainspring you wind with a key, or weights on cords or chains that you pull up. The spring or the weight is just stored energy, slowly let out. A mainspring is under a great deal of tension even when the clock has "run down," and it can hurt you badly if you take a movement apart without letting that tension down first. More on that under tools.
2. The train. A row of brass gears (clockmakers call them wheels) and their small steel pinions that carry the power up from the spring and turn it into the slow, steady motion of the hands. Each wheel turns on a steel pivot that rides in a hole in the brass plates. Those pivot holes are where nearly all the wear in an old clock happens.
3. The escapement. This is the heart of the thing and the part that goes "tick." A toothed escape wheel at the top of the train is caught and released, one tooth at a time, by a rocking piece called the anchor (or verge, or pallets, depending on who you ask). Each release lets the train move ahead one tiny step, and each catch gives the pendulum a little push to keep it swinging. Most American shelf and wall clocks use a simple recoil escapement; if you watch the second hand on a fine regulator you'll see it doesn't jerk backward at each tick, and that one has a deadbeat escapement, which is more precise and more expensive.
4. The pendulum. A swinging pendulum takes the same time for every swing, long or short, as long as its length doesn't change, and that is what makes the clock keep time. Turning the little nut under the bob (the disk at the bottom) to raise the bob shortens the pendulum and makes the clock run faster; lowering it makes the clock run slower. The pendulum hangs from the movement on a thin flat spring called the suspension spring, and is pushed by a wire from the anchor called the crutch. Remember the crutch. It comes up again.

A clock that strikes the hours has a second, separate train alongside the time train, with its own spring or weight, that is let off once an hour by the time train. On most American clocks a count wheel (a notched disk) decides how many blows to strike; on better clocks a rack and snail does the job. The difference matters when the clock strikes the wrong hour, so I'll come back to it.

Nine times out of ten the clock that "just stopped one day" stopped because the oil that was put in it decades ago has dried to varnish and the dust has stuck to it. The cure is a proper cleaning. A proper cleaning means the movement comes completely apart: every wheel out from between the plates, every part cleaned, every pivot inspected and polished, every hole checked for wear, and the whole thing put back together and oiled fresh.

Here is what I don't do, and I'd ask you not to either:

• Dunking the whole movement in a bucket of cleaner without taking it apart. Yes, it will sometimes run afterward, for a while. It also washes the dirt into the pivot holes and leaves it there, and it doesn't let you see the worn pivots and egg-shaped holes that were the real trouble. I did this to my second clock. It ran for four months.
• Spraying it with anything from a hardware-store can. See oiling.
• Taking apart a movement with a wound mainspring. If the clock is stopped, the spring is not necessarily unwound. Let it down first, with a proper let-down key, or find someone who can.

The way I do it, in short: let down the springs, note or sketch where every wheel sits (I use a cheap camera now, one picture per step, and the film goes to the drugstore before I reassemble), take the plates apart, put the parts in a clock-cleaning solution (the commercial stuff from a clock supply house, or an ammonia-based cleaner if you have ventilation), scrub with a soft brush, rinse, and dry thoroughly. Then I go through every pivot with a loupe. A pivot that's scored or rough gets polished; a pivot hole that's worn oval gets a bushing, which is a little brass plug with a new true hole in it. Bushing is where hobby stops and craft begins, and it took me a good two years to do one I was happy with. If a clock needs several, that's when I'd suggest a professional for your first few.

When not to try at all: anything with a fusee (a cone-shaped pulley and chain), any French or German movement with a platform escapement instead of a pendulum, anything with a broken mainspring (they're cheap to replace but dangerous to handle), any clock with real family or dollar value that you'd be sick about, and any clock where somebody before you has already "fixed" it with a soldering iron. Those all go to someone with more experience than a basement.

Listen to a healthy clock and it goes tick ... tock ... tick ... tock, evenly spaced. Listen to a sick one and it goes tick-tock ...... tick-tock ......, with a limp. That limp is called being out of beat, and it is far and away the most common reason a clock runs for a few minutes and then stops. The pendulum is getting a good push on one side and a weak one on the other, and as soon as the swing settles down a bit the weak side isn't enough.

Two ways to fix it:

1. The quick way: tilt the clock. Put a matchbook or a folded card under one side of the case and listen. If the ticks get more even, try more; if worse, try the other side. This is how millions of clocks on millions of mantels have run for a century, slightly crooked. Fine for a shelf clock that isn't going anywhere.
2. The right way: adjust the crutch. On most American movements the crutch is a wire coming down from the anchor that the pendulum rod hangs in, and it can be bent, very gently, to one side or the other. Bend it a hair toward the side that gets the weak tick, then listen again. Small moves. Several tries. On some clocks the crutch is designed to slip on its arbor with a little firm pressure instead of bending. Either way the clock will then be in beat when the case is level, which is what you want.

How do you know which side is weak? Hang the pendulum, push it gently to one side until it ticks, and note how far you had to push. Then the other side. The side that needs the bigger push is the side the crutch needs to move toward. It sounds harder than it is. Ten minutes of listening will teach you more than I can write.

Please, please do not oil a clock with 3-in-1, WD-40, sewing machine oil, motor oil, or anything else from the garage. Household oils gum up as they age and the penetrating sprays wash away what little good oil is left, and either way the clock runs for a month and then stops harder than before, with a coat of goo on every part that then has to be cleaned off. I've had more than one clock come to me "after my son-in-law oiled it."

Use clock oil, from a clock supply house; a small bottle costs a few dollars and will last you years. Apply it with an oiler (a needle-like tool with a tiny cup on the end) or a fine wire, and put a drop only at the pivots, where the steel turns in the brass plate, so that the oil sits in the little cup (the "oil sink") around each hole. One small drop each. If oil is running down the plate, you used ten times too much. Do not oil the gear teeth. They don't need it and it only collects dust. The mainspring gets a very light film of its own grease when it's out of the clock, and that's a job for cleaning time, not now.

A clean, properly oiled clock should go five to eight years before it wants doing again. If it keeps stopping in between, oil isn't the answer; something's worn or out of beat, and adding more oil will only hide it for a while.

You need surprisingly few, and one of them is not a hammer, no matter what the clip art says.

• A let-down key (or let-down tool). A handle that fits the winding arbor and lets you release mainspring tension under control while you hold the click off. This is the one tool I'd tell you to buy before you open a clock. It's not expensive and it may save you a finger.
• Mainspring clamps to hold the springs coiled while the movement is apart, and a pair of leather gloves for when a spring comes out of its barrel.
• Screwdrivers, good small ones with hollow-ground tips, and a set of tweezers. I made my own brass tweezers because steel ones scratch.
• A loupe, about 4x, and a second one at 10x for looking at pivots.
• Pegwood, which is just little sticks of wood you sharpen and push through the pivot holes to clean them. Oldest tool in the trade and still the best.
• Clock oil and oilers (see above).
• Brass wire and fine pliers for the pins that hold the plates together.
• A bushing tool and assorted bushings. This came later and cost more than the rest combined. For your first year you can send a movement out for bushing.
• A movement stand I made from angle iron so the movement can run on the bench without its case while I watch it.
• A good light, a clean bench (mine is an old kitchen counter with a lip so parts don't roll off), and a muffin tin for keeping screws in the order they came out.

Dorothy has taken photographs of most of these with the old Instamatic, and my grandson has promised to show me how to get them onto the computer with his scanner over Thanksgiving. Until then you'll have to take my word for how they look.

The 1920s oak kitchen clock. This is the one the neighbor gave me, and the one that started it. An eight-day, spring-driven, time-and-strike "gingerbread" clock, with a pressed-oak case full of scrolls and a little scene stenciled on the lower glass, made by one of the Connecticut factories that turned these out by the hundred thousand. When I got it the movement was black with old oil and both mainsprings were "set," meaning tired and limp. New springs, a full cleaning, two bushings on the strike side (done by a professional; I wasn't ready), and it has run on the kitchen wall since 1995, losing about a minute a week, which Dorothy resets on Sundays.

The schoolhouse regulator. An octagon-top, short-drop wall clock with "REGULATOR" in gold on the lower glass, the kind that hung in every schoolroom and railroad office around 1900. Bought at an estate sale for the price of a good lunch, because it "didn't work." (Grade-school teachers: the word Regulator on these was a sales word. A true regulator is a precision clock; this is a good eight-day time-only movement in a handsome case.) It was out of beat and filthy, nothing more. Two evenings of work. It hangs in our front hall and is the best timekeeper in the house.

The black mantel clock. A heavy "black" mantel clock of about 1900 with fake marble columns and gilt feet. The case turned out to be wood with a celluloid veneer that looks like marble, which was a popular finish then, and it cleaned up beautifully with nothing stronger than soap. The movement was a good eight-day time-and-strike with a cathedral gong, and it needed a new suspension spring (someone had bent the old one trying to "fix" the beat) and cleaning. Now it strikes on the half hour in my son's living room.

The ogee. A plain rectangular case with a big curved molding around the door, weight-driven, thirty-hour, from somewhere between 1850 and 1890. Homely, honest and almost impossible to kill. The weights had been lost; I made new ones from iron pipe filled with lead shot and capped, weighed to match a friend's original. Wound every night, as it was meant to be.

The cuckoo. Not my favorite kind of clock, but Dorothy's aunt's, from a trip to Germany in the 1950s, so it counted. Weight-driven, one-day movement, with the bellows that make the cuckoo sound worn through. New bellows tops (you can buy them and glue them on), a cleaning, and a great deal of patience with the little wire that lifts the bird. It cuckoos. Dorothy is happy. I have moved it to the room farthest from where I sleep.

Ones I couldn't save: a beautiful French carriage clock with a platform escapement (sent it to a professional and it came back perfect, for a fee I won't print); and a 1940s electric kitchen clock, which is not a mechanical clock at all and whose synchronous motor was simply done. I keep it on the shelf as a reminder to know my limits.