It was just another $20 yard-sale purchase — or so Liz Rizzo thought. The Lanikai resident bought three wooden boxes in the 1980s at a Scottsdale, Ariz., estate sale because she thought the containers were attractive. She intended to get rid of the tools stored inside.

Rizzo later discovered that she had obtained rare tools from the 1920s that were used in the manufacturing of early models of Ford automobiles. Her set of gauges and weights — also called "Jo blocks" after their Swedish inventor, C. E. Johansson — were the personal set of Johansson himself, according to a note inside one of the boxes.

They're believed to be worth thousands of dollars — but exactly how much, Rizzo doesn't yet know.

"I would like to learn the value, the historical value," said Rizzo, a sales consultant in her 50s. "Is this something I should sell? Does a museum want it? I want it to go the right people because it's so rare and valuable."

Rizzo hopes to find the answers she's looking for during a taping of the national television series "Antiques Roadshow," Saturday at the Hawai'i Convention Center. Rizzo was among nearly 8,000 Island residents randomly selected to attend the much-anticipated appraisal event. Tickets are no longer available, but fans can catch the Hawai'i episodes next year.

Three Hawai'i-based episodes will be produced during the one-day taping, and approximately 15 to 20 appraisals will be selected for each one-hour show.

"I love it," said Rizzo, a die-hard fan of PBS' most-watched prime-time series. "It's been my dream to be on the show."

The "Antiques Roadshow" staff, appraisal team and crew are just as excited about the Hawai'i stop, said executive producer Marsha Bemko, via telephone from Boston.

"We don't normally travel this far, so that's a treat," Bemko said, "and we're looking forward to seeing things in Hawai'i that we won't see in other places."

Such items include royal Hawaiian objects, collectible aloha shirts and "other things indigenous to Hawai'i," she said.

The four-time Emmy-nominated series, in its 10th season this year, attracts more than 12 million viewers each week. The show features bite-sized appraisals with a mix of history, suspense and an answer to the all-important question: Is it trash or treasure?

"It's fascinating just to see the different kinds of things people put value on," said Kane'ohe resident Peter Dyer, an avid viewer who also received tickets to attend the event.

Event-goers will receive free verbal appraisals for one or two items by antiques experts from the country's leading auction houses — including Christie's, Doyle New York and Sotheby's — and nationally known independent appraisers.

About 70 to 80 appraisers will be on hand to cover more than 24 specialties, such as Asian works of art, jewelry, musical instruments, photographs and toys.

Dyer plans to bring with him a wooden bureau, which he traces back to his great-grandmother's home in Hartford, Conn. He saw a similar piece in a Sotheby catalog and wondered if it was the same type.

"I'd like to know if it was the kind of piece the Sotheby catalog suggested it was because if it is, it's valuable," said Dyer, 63, a retired university administrator. "I'd like to insure it properly."

He's also thinking about bringing in an antique portrait of his great-great-great grandmother or a War of 1812 musket, passed on to him from his grandfather.

The items are heirlooms, and Dyer isn't sure how much they're worth. Whatever the outcome, Dyer is just excited he'll be a part of the show.

"(My wife and I) watch it because I have a New England heritage, and I've always been interested in antiques," Dyer said. "We find it fascinating."

It's easy to understand the appeal of "Roadshow," Rizzo added.

"The excitement of having something valuable is great, but being able to learn something about it, especially something rare, is even better," she said.

Reach Zenaida Serrano at zserrano@honoluluadvertiser.com.