(FORTUNE Magazine) – Just before last Christmas, at the height of the tourist season in the Dominican Republic and thus a time of serious beer consumption, a key diesel engine suddenly failed at the big Cerveceria Nacional Dominicana brewery in Santo Domingo, drastically cutting production of Presidente Pilsener, the Caribbean's bestselling beer. The first thing the brewery's worried executives did was to telephone a small Milwaukee company called In-Place Machining--not because of its location in U.S. beer country but because it specializes in the toughest repair jobs in manufacturing: fixing broken machinery right on customers' premises while the production lines are rolling.

That same day, In-Place flew two technicians and 2,000 pounds of specialized machining tools to Miami. There the men were met by a chartered plane sent by the brewery and flown to Santo Domingo. The technicians went to work around the clock, trading 12-hour shifts. Within two days the diesel engine was running again, and smiling Cerveceria Nacional executives were saved from a miserable holiday.

That kind of mission is all in a day's work for a little company with an unassuming name. In-Place has performed such impressive feats as restoring electrical power to an isolated Canadian Eskimo village above the Arctic Circle in the middle of winter and stitching together the engine of a cruise ship on a Caribbean voyage as the passengers dined and danced on the decks above. Its technicians have resuscitated nuclear power plants, gold mines, and concrete factories, put the swing back into a railroad bridge spanning the Mississippi River, and flown a four-ton crankshaft-grinding machine to the Saudi Arabian desert to fix a natural-gas compressor--sometimes at great peril to their health.

Little wonder that the company's founder and chairman, Ralph H. Eder, 81, a manufacturing pioneer, is often compared to Paul "Red" Adair, the Texan who for 40 years famously put out oil well fires around the world, including 117 of the ones ignited 12 years ago by Saddam Hussein's troops in Kuwait. Adair and his crew of 12 averaged 42 jobs a year before he sold his company in 1993. Eder's 75 employees handle 250 to 300 jobs a year, so they put out a lot more fires.

In-Place Machining isn't a maintenance and repair shop in the traditional sense. Most routine repair jobs, such as maintaining industrial equipment under warranty, are handled by the legions of technicians on the rolls of big equipment makers like GE, Westinghouse, and Siemens. But even those powerhouses often call on In-Place for the most difficult on-site repair jobs, especially for big turbines and other gear that can't be moved into a machine shop.

Afloat or ashore, In-Place tries to make its repairs without interrupting its client's operations. To do shipboard "voyage repairs," as Eder calls them, a team of technicians might fly to Central America to meet a ship at the Panama Canal and sail across the Atlantic or Pacific as the machinists work below deck. A typical ship might have three generators onboard, with two in use and the other as a standby. If one of the generators fails, the ship can still sail. "The operator doesn't want to sit in port fixing the broken one," says Eder, "so our machinists work on the job while the ship is sailing and disembark at the next port."

To make its tricky repairs, In-Place uses highly specialized portable tools that it modifies for each job and then transports to the work site. Its warehouses in Milwaukee are jam-packed with thousands of components to build such tools, augmenting its six ready-to-ship tool cribs--containers that serve as portable tool rooms. Smaller competitors, in contrast, generally use only off-the-shelf tools. In-Place's employee roster is highly specialized too, boasting not only master machinists but also certified welders, engineers, machine-tool rebuilders, and optical alignment technicians.

Both Ralph Eder and his son Jonathan, 42, the company president, call In-Place's ability to assemble a tool to fit a particular job the key to its success. With $12 million in annual sales, the family-owned company isn't big, but it dominates its specialized niche.

In-Place grew out of the elder Eder's lifelong attraction to the sea and his love of engineering. Ralph's father owned a small manufacturing company in Milwaukee, and Eder displayed a technical bent early on, building crystal radios and model boats and airplanes, and fixing everything from gasoline engines to washing machines.

The sea beckoned at an early age. When Ralph was 15, he started going out on commercial boats as a helper. He had read books about the South Seas and dreamed of one day sailing them. The dream became a reality, although not in the fashion he had envisioned, when he graduated from the U.S. Naval Academy in 1944 near the top of his class. As an ensign and a lieutenant junior grade, he served in turn as a deck, engineering, and electrical officer aboard the battleship Missouri in the Pacific during World War II. (The ship was hit by a kamikaze pilot, but no one aboard was killed.)

That experience came in handy after the war. Eder started and sold a clutch of small electronics companies, and by the 1960s he was making optics for the space program. But business dried up after the U.S. won the race to the moon, and Eder wondered what to do next. A friend prodded him by asking, "What else can you do?" Eder replied, "I can fix ships."

As it happened, in 1971 longshoremen called a massive strike at East Coast ports. Suddenly large numbers of oceangoing freighters and other ships from around the world started showing up in Milwaukee and other Great Lakes ports. To service those ships, Eder founded Ship Repair & Supply Co. He was soon providing vessels with everything from rat poison to radio parts, as well as fixing machinery onboard--adjusting air, steam, and electric whistles and horns, repairing cargo and anchor winches, reviving propulsion engines. Eder hired scuba divers to clean hulls, rudders, and propellers, and bought two seagoing tugs to tow ships in distress.

But it was his adoption of a pioneering technology that would help transform In-Place, as it was rechristened, into a company able to perform difficult jobs anywhere. The engine housings of a big ship are typically made of cast iron. When such a housing fractures, it can't be easily repaired because cast iron is porous, and hence not amenable to welding. Fixing a crack on the spot would require more sophisticated technology, and Eder found it in a variation of a 19th-century technique called metal stitching.

The process starts with technicians applying a penetrating dye and magnetic particles to a crack so that they can accurately define its dimensions. The broken pieces are then positioned, aligned, and firmly held together by special fixtures and clamps. Technicians next drill a pair of holes on either side of the line of the fracture and, using a pneumatic chisel, fashion a channel between the holes. A so-called stitchlock forged of a highly malleable alloy is then pressed into the channel and screwed into the holes. Additional holes are drilled along the length of the crack and filled with stitchlocks, each lock screwing into the adjacent one. That creates a pressure-tight joint and restores rigidity to the casting. The end result, with rough metal removed, looks like the stitches of a skilled surgeon.

Metal stitching has given In-Place a built-in edge because use of that important metal alloy is proprietary; In-Place owns exclusive North American rights to advances in the technology. Besides shipboard repairs, In-Place uses metal stitching to fix steam engines, gear housings, machine-tool bases, and many other industrial devices.

In-Place has also developed new ways to work on huge machines like turbines without disassembling them. In one such feat, Ralph Eder led a team that figured out how to fix a "journal"--a shaft that rotates on soft metal bearings within steam turbines, power blowers, and propellers. Sometimes journals are damaged because of insufficient lubrication, and their surfaces must be restored to their original smoothness. Or their bearings may fail and need replacement.

Taking apart a big turbine is highly expensive and time-consuming. Eder invented a portable device nicknamed a squirrel cage that holds a machining bit or grinder. The cage, which is six to 60 inches in diameter, sits on the journal and rotates around it, polishing its surface. The squirrel cage can save an electric utility hundreds of thousands of dollars on a single job by drastically shortening the time that a turbine must be taken out of service.

In more recent years In-Place has applied sophisticated software techniques that simulate how metal objects behave under stress. Engineers can then repair structures like bridges to ensure long wear of their most critical parts.

Such abilities have let In-Place perform some unusual tasks. They include polishing the huge mirror at the main telescope at Mount Palomar Observatory near San Diego. The company has also machined the surface and drilled precision holes in an unearthly looking giant aluminum sphere at the Lawrence Livermore National Lab laser fusion facility. Last February, In-Place delivered a specially built mirror-polishing machine to the University of Arizona's Stewart Observatory. Technicians will use the machine, the largest such device in the world, to polish two 26-foot-wide telescope mirrors they are making there now.

From time to time In-Place will do a big job in Milwaukee or at one of its three service centers, in Chesapeake, Va., Chicago, and Los Angeles. This might involve making exceptionally large metal rings, some with a diameter of 60 feet, for hydroelectric plants. But those are exceptions.

Even for the best of surgeons, not every operation goes according to plan. Sometimes an In-Place technician can make a mistake too, perhaps machining a part to the wrong size. That usually means the work will take longer than estimated, and instead of making a profit, In-Place may lose money on the assignment. Still, says Jonathan Eder, "we always manage to do the job."

As you might expect, working at In-Place requires a large dose of resolve. When an emergency call comes, machinists and technicians must move almost as fast as firemen sliding down a pole. Its specialists are on call around the clock. They have been pulled from weddings and christenings, and roused from their beds at 3 A.M. to leave for a distant job that might keep them from home for as long as eight weeks. Their jobs can be hazardous too. They must work in steel mills while red-hot metal rolls by and in underground tanks where their air supply is strapped onto their backs. But no In-Place employee has been killed on the job, and there has been only one serious injury--when an impatient machinist tried to push hot metal chips away with his bare hand, losing a finger.

On a recent day In-Place had six teams scattered around the world in locales that ranged from a dry dock in Panama, where technicians were fixing the rudder on a freighter, to a parking garage in Albany, N.Y., where they were repairing big blower fans. "Much of this type of work was done before in machine shops by laborious and time-consuming disassembly," says Ralph Eder. "We introduced the concept that says, 'We can fix almost anything, anywhere.' "

That's a big improvement for clients that can't afford downtime--and for In-Place, it's a long way from selling rat poison to ship captains.

FEEDBACK fortune_letters@fortunemail.com. Stories from the Industrial Management & Technology section can be found at fortune.com/imt. Executives in manufacturing and research and others eligible to receive FORTUNE's Industrial Edition can subscribe by calling 888-394-5472.