Ronald Randklev was nothing if not precise.

Whether inventing products that served as the bedrock for 3M’s dental division, helping solve rocket fuel filtering problems for the nation’s first space missions, hanging perfectly symmetrical picture frames or eating dinner at 5:23 p.m. nightly, no task was too big or too small to fall outside his exacting purview.

Randklev, 87, died on Sept. 5 due to complications from Alzheimer’s disease. Even his death, said his son-in-law, was handled with a smile and calmness, as if it had arrived right on schedule.

“The heart and soul of the guy was a scientist, a dyed-in-the-wool kind of scientist. He was one of those guys who had bushy eyebrows and would draw algorithms on his morning newspaper,” said Rick Leepart, his son-in-law.

Randklev grew up in the age when science could solve anything, and lived with a tenacious desire to learn, grow and adapt. “It was his whole soliloquy. He really lived it and never thought it to be extraordinary,” Leepart said.

Randklev was born and raised in Crookston, Minn., and graduated from Bemidji State University with a chemistry degree. During the Korean War, he was stationed in San Antonio with the Army Air Corps where he worked in a research lab on classified projects with former WWII scientists from Germany and the U.S.

In the 1950s and 1960s, he joined a team of chemists that helped solve the filtering and cleaning of rocket fuel used in the Atlas Missile project. The bulk of his career — 27 years — was spent at 3M, where he often worked solo. It was during this time he invented products, including the white mixture that replaced silver fillings, which eventually led to the creation of the company’s dental division. 3M honored him with its Technical Achievement Award and Innovator of the Year Award for this work.

“Ron invented all that white stuff that is in my teeth and in yours,” Leepart said. “He was a true innovator and true entrepreneur. One of the few guys that came up with the real creations to come out of 3M.”

The man’s discipline translated into a regimented daily routine: awake at 6 a.m., a 3-mile walk before and after work, followed by dinner at 5:23 p.m.

He was humble despite all of his successes, which included 19 individual patents.

“He would quietly hang each new patent on his wall at home,” Leepart said.

Randklev retired early, wearied by the abundance of new chemists in his previously solitary lab. But he didn’t stop. He and wife Arlene moved to their final home together on Lake Superior in Grand Marais, where he found new projects to master, like organic gardening, construction or trout fishing.

“The city was going to build an asphalt plant near his home, so he set up a chemistry lab in his home and figured how much acid rain would be produced and would slide off the freeway because of it. He calculated how bad it would be for the environment and they never built the plant — shut the whole plan down,” Leepart said.

And when a doctor told him he needed glasses, Randklev thought that was ludicrous. Instead, he researched how to strengthen vision through intense focus and relaxation.

“He would spend hours a day in his yard focusing on ships — through some sort of pinhole — and then relaxing his eyes. He went back to the doctor a year later and had 20/20 vision,” Leepart said.

“He was so loving, so sweet, so dear,” Leepart said. “He worshiped Arlene. They always called each other their sweetheart.”

Randklev is survived by his two daughters, four grandchildren and three great-grandchildren. Memorial services will be held at 10 a.m. on Oct. 2 at Mattson Funeral Home and Cremation Services in Forest Lake.