Jake Vandergrift, a builder, and Al Kincaid, a carpenter, are walking around these bright spring days with an extra bounce in their steps, a hard job finished and their faith in human goodness restored.

It was December 1981 when Vandergrift read in the paper about the latest local atrocity: the murder of Robert Duncan, who had taken a night job at a Severna Park service station to earn money for his two children's Christmas presents. Duncan was shot dead in a robbery before he had cashed his first paycheck.

Like many who read the story, Vandergrift wondered, "What can I do?" Unlike others, he did something.

Last week, Robert Duncan's widow and children moved into the first house they have ever owned, a new cedar-sided, 1,000-square-foot, three-bedroom bungalow, from the deck of which they can watch the sun glinting off the backwaters of the West River.

Vandergrift and Kincaid put it up, partly at cost and partly for free. They cajoled and begged and bartered with contractors and subcontractors for cement and appliances, wiring and plumbing, carpet and drywall. They banged nails and cut timbers, and in the end, the Duncans had a home.

"What I wanted to do," said Duncan's widow, Claire, "was stabilize the kids. They'd moved so many times." She settled into her new couch in her new living room and sighed. "This is my home town. When I get to Galesville, I can rest. I feel like I'm really, really home."

Tragedy had struck the Duncans twice. On Dec. 9, 1979, their rental house in Cape St. Clair burned to the ground in the middle of the night and they lost everything. "Robert and I were hurt in the fire," she said. The children, Laurie, now 15, and Robert Jr., now 13, were not injured.

"Daddy put his bare back to the fire and sheltered us out," Laurie said.

"Then he came back in and got me, because I was too afraid to move," said Claire Duncan. "He was pretty good. He was good."

Exactly two years later, on Dec. 9, 1981, Duncan, who worked days for the Anne Arundel County roads department, called his wife at 11 p.m. to say he was closing up the service station and would be home shortly. It was the last she heard from him. Police found his body the next morning. He had been shot three times in the head.

Claire Duncan went into shock. When she recovered, she took the children 20 miles south to her father's house in Galesville. She never went back to the Severna Park house where they had lived. Friends moved the family's belongings. "Even now," she said, "I have a hard time driving by the gas station."

Meanwhile, Vandergrift was thinking about what he could do to help. He knew Claire Duncan's brother, Wells Dixon, and asked him if she needed help with a house. Dixon said, yes, and said that although her salary as a stenographer-clerk for the state government was limited, she had some money from insurance.

They determined that if she bought the lot she wanted in Galesville, she'd have about $40,000 left for a house. Vandergrift, who designs and builds expensive waterfront homes, called Kincaid, an acquaintance who builds Viceroy kit homes.

"Jake said, 'Can we do it for $40,000?' " Kincaid recalled. "I said, 'Yes, with a lot of donated time and materials.' "

Vandergrift posted notices around Anne Arundel asking for assistance. Then he got on the phone to his contacts in the building business and asked for help, which many, to Vandergrift's astonishment, agreed to give.

Last winter, trucks from E.L. Gardner Inc. rolled into Galesville to deliver the concrete for footings, free. Trucks from J.F. Gomoljak brought the foundation blocks, free. Kincaid and a helper framed the house and closed it in, free. Noland Co. sent plumbing supplies and David Owens and Stanley Elsey put them in, free. Branch Electric, Tri-State Electric and Baltimore Gas & Electric supplied electrical equipment and Simpson Electric and Joe Tyce installed them; Wilken Gypsum sent the drywall; Kitchen Wholesale sent $1,800 worth of cabinets--all free.

J.R. McCrone engineered the site; Red's Dove graded it; Amana sent a refrigerator and stove and Winslow sent the paint; Annapolis Landscape Co. is due any day to finish the landscaping. Again, it was all free.

Others worked at cost and without profit hanging drywall, digging the well nd septic tank, installing heating and air conditioning and tile and carpet.

The job didn't go quickly, said Vandergrift, who coordinated the project. "It's hard to get on the phone to somebody who's donating and yell at them to hurry up," he said. But in time, the job got done.

Last week, Claire Duncan and her children moved in. "I stood out in the yard for 10 minutes, screaming for joy," she said.

Vandergrift and Kincaid have been joyful all along. "For us it was a real uplift to find people do care," Kincaid said. "It renewed our faith in the contracting business."

When Claire Duncan collared Vandergrift on moving day to formally thank him, he shrugged and said, "Don't thank me. I had a good time."

Said Vandergrift, "I wanted something positive to come from what happened to Robert. I didn't want to just turn off the TV and say, 'Okay, it wasn't me.' "