RONALD HAYES Pearson's remarkable silversmithery, with its now-you-see-it, now-you-don't twists and turrs, calls to mind obscure mathematical forms.

But to Pearson, the 64 or so objects in his show of recent work now open through Oct. 15 at the Renwick Gallery of Art are useful things, the results of his hard labor-necklaces, forks, spoons, knives, earrings, playthings, letter openers.

He is one of a growing body of craftsworkers who aim to make a living while producing and selling beautifully designed and carefully crafted objects. He rarely makes one of a kind. Because they are multiples, they can be sold at far less than the price of one-of-a-kind originals. He is also a member of a small band of craftsworkers who have made their living with their eyes and their hands for 30 years, pioneering the way.

Pearson is not a man to talk of his work as fantasy or philosophy or other abstractions. He doesn't find it necessary to glorify his occupation by calling himself a goldsmith or silversmith or even a metal sculptor - though he was one of the founders of the Society of North American Goldsmiths. As plainly spoken as his metal surfaces, he is satisfied with being a metalsmith. He is a man who tests his silver forks by having his friends eat with them.

"There are two principal ways of ornamenting metal work. One if to work it in a horizontal way, flat pieces embossed or engraved, for instance. The other way is mine - to work in three dimensions," Pearson said the other day. He came to town to see the installation of the show by Renwick associate curator Mike Monroe.

Pearson may be best known for Vision, a sterling silver flatware produced by International Silver Company. In 1960, he entered the International Flatware Design Competition, along with 22 other designers from 14 countries. His design for silver flatware, a complete place setting of various-sized forks, knives and spoons, was the one selected for production.

Vision was certainly one of the first contemporary silver services to be produced by a large company, and it inspired other manufacturers to follow suit. Even today, Vision looks contemporary, clean-lined and beautiful as though it was designed only to serve the purest, nitrate-free, home-grown natural food.

"I told the company," Pearson said, "that I bet them the design would sell fairly slowly at first but gain in momentum as the years went by. And sure enough, I talked with one of them the other day, and he said it was selling better now than ever. Unfortunately, my royalties ended after five years, but I liked working with them."

In 1976, Pearson was asked by the Smithsonian Institution to design a modern version of the old fiddleback flatware, to be produced (with royalties to the Smithsonian) by Steiff silver company. "There was only a fork and spoon, once owned by John Quincy Perrot, Smithsonian assistant secretary. "It seemed wrong to just have a knife designed to go with it. So we asked Pearson to work out a completely new design, based on the pieces we had."

In the show at the Renwick, you can see how the design developed. An early model was favored by Steiff for the lift at the end of the handle, the gentle upsweep of the center line, the concave back, the thin top view, the thick side view, the triangular cross section and a ridge at the juncture of shank and tines. But Steiff wanted some small changes to the underside. The Smithsonian committee suggested changes here and there. And so Pearson made a number of models, some with modifications so slight it would take a real expert holding it in hand to point out the difference. Yet it is these fine points which make a fork or knife feel and work right.

As a knife label explains, "The handle must fit comfortably in the user's hand, it must allow him to exert pressure upon the blade and its edge must be correctly aligned for cutting." There are other considerations - edges of the salad forks have to be beveled to separate the food. To dig into food, the teaspoon is more pointed than the place (dinner or table) spoon, which is large and deep to spoon liquids. The butter spreader also has to have a cutting edge for cheese and fruit.

The place (dinner) knife's third design - the one accepted - is, happily, a real design on its own rather than a strict copy of the place fork's handle, though it sits nicely with the more traditional spoon and fork. Not so incidently, the knife is far and away the most beautiful of the three pieces. The pattern, called "Smithsonian," is just now on the market.

The other day Pearson, now 53, stood in the tall, old upstairs gallery of the Renwick, looking in that huge room still the large man that he is. It is not hard to see him as a Merchant Mariner, as he was for three years during World War II, or bringing his boat about in the waters off Deer Isle, Maine, where he has his home and studio. His hands are in proportion to his height. They seem too big to handle the tiny fine gold and silver wires he twists into earrings. Yet his face with its inquisitive nose, brown eyes and rather stern lips has more the air of a professor than a sailor.

And, indeed, he is a teacher, as well.In his workshop he has a staff of up to nine. They come to him under a government program in which he pays a portion of their salaries and the government pays the rest while they are in training for six months. For the next six months, they study half time and then work making his designs. He has taught other places as well - the School for American Craftsmen at Rochester Institute of Technology in New York, the Haystack Mountain School of Crafts in Deer Isle and the Penland School of Crafts in North Carolina.

He is an independent man. While he was checking over the exhibit, he explained that he had always wanted an occupation that gave him the freedom to work as he pleased."When I got out of the Merchant Marines in '47, I decided I had to make a living. My father had always been an independent soul. I admired his freedom. It's been hard at times, but I always believed that it's possible to do what you want to do, if you're willing to work hard at it.

"My father (Ralph M. Pearson) was a teacher, an artist and a writer. He used to have summer classes on an 100-foot schooner built to haul granite. I was the deck hand. My mother was first mate. I suppose the first time I thought about working on metal was when I was 12 and we were sailing to Philadelphia. Dick Meredith was teaching pewter in the hold of the ship, and I worked with him. Later I took shop in school. At home I grew up with art, painting and working with clay.

"When I went off to the University of Wisconsin, I studied political science, but that was only six months before I joined the Merchant Marine (1943). For the next three years, I saw the world - all over: Dunkirk, Ireland, Scotland, North Africa. I didn't pay much attention to the iron work then. I didn't know I had the interest.

After the war Pearson learned his trade at the School for American Craftsmen at Alfred University, N.Y. "I could only afford to go for a year. Back then, the school scorned jewelry-making. But when I had to quit and go to work, my teacher, Philip Morton, said, 'Look here. You're going to have to know jewelry to make a living.' And so he gave me a crash course at home."

With the $50 in his pocket and a $500 loan from a family member, Pearson set up shop in Alfred in an ex-chicken coop with a spinning lathe, and some bronze. He spun bowls, candleholders and dish forms. This was the era of the Museum of Mordern Art "Good Design" exhibits which did so much to educate Americans in the delights of pure, unornamented form. Several of his bronze holloware pieces were chosen for the exhibits from 1950-54, and some still surface in MOMA's design gallery.

In 1950, the metalsmith moved on to Rochester, N.Y., selling the spinning shop and some designs. About then, he took up jewelry seriously. And two years later, with three other craftsmen, he organized Shop One, a retail shop for craftwork in Rochester, one of the first such craftsman-owned ventures.

As a designer, Pearson worked on bronze desk accessories will Metal Arts Co., and with Hickok Jewelry Manufaturing Co. In 1970, while working on the problem of perpetual motion (probably from trying to keep his silver pieces from rolling while he was working on them), he designed a toy, produced by Creative Playthings as Crazy Roll. A silver version is in the show. Among his many commissions are an altar cross at the Church of the Redeemer, Baltimore.

In 1971, Pearson and his first wife were divorced (they have four children, the youngest is an apprentice weaver at Boston University). And "I decided there was no reason I couldn't go back to the sea, where I belonged." So he moved to Deer Isle, Maine, and a big old Victorian house, remodeled with the help of the four craftsmen who moved with him.

It was there he met his wife, RickaFeely, then the executive director of the Society of North American Goldsmiths. They were married Dec. 11, a year and a half ago, walking through the woods to the ceremony near their house. They have a baby, 8 weeks old, named . . . "Are you ready?" asked Pearson: "Alexander McAllister Feely Pearson."

The workshop is in a structure that links the house with the barn. The nine staff members, with Pearson working along on production as well as design, make about 250 pieces a week to sell to 50 retail shops across the country. Pearson sketches the piece first. He usually hammers out the square silverstock on an anvil with a hammer called a crosspeen.

Some of his more unusual piece - a letter opener, a circular neckband - are made "with an old blacksmithing technique: twist in one direction three turns, then forge it back to a square, then twist in reverse one and a half turns," he explained. Another piece, a circle, is twisted 90 degrees.

These are the pieces which remind one of the fabled Mobius band, defined by Webster as "a one-sided surface, formed by holding one end of a rectangle fixed, rotating the opposite end through 180 degrees and then applying it to the first end." Or as the 1935 song went, "The music goes round and round and comes out here."

Judging by the pieces in the Renwick shop, the prices vary from $26 for a pair of plain earrings up to almost $900 for a gold bracelet or a gold necklace set with a precious stone.The business is prosperous enough that he's able to afford a boat, even though his 7 a.m. to 7 p.m. days, seven days a week, don't leave too much time to sail it.

"But I'm trying to take things easier," he said.

"Oh yes," said his wife."Even in the evenings, I can tell, you're still thinking about the next design."