Relational, which has teamed up with a large public pension fund to push for a breakup of Timken, has heard from other investors supporting its campaign and believes that an "overwhelming majority" of Timken's public shareholders want a separation of the company, Whitworth said.

Relational is Timken's largest shareholder, and together with the California State Teachers' Retirement System (CalSTRS), owns a 7.31 percent stake in the company.

In November, Relational and CalSTRS said that the diversified manufacturer should split its steel and bearings businesses to increase shareholder value. Timken has said it had considered the proposal with outside advisers but determined the time is not right for such a move.

"It appears they're hoping that if they just ignore it, it will go away. But this is not going away because we're going to persist until they maximize the value of these assets," the investor told Reuters in an interview.

The investors sent a letter to the company's board earlier on Tuesday. They have said Timken is significantly undervalued due to its combination of two different businesses and separating those units would maximize shareholder value.

"We continue to believe the company has significant cost, technology and revenue synergies between its bearing and steel businesses, as well as diversification benefits in continuing to operate under its current structure," Timken spokesman Dan Minnich said in a statement.

Shares of Timken, which makes mechanical components and high-performance steels, rose 2.2 percent to $57.49 on the New York Stock Exchange on Tuesday, valuing the company at more than $5.4 billion. Timken's stock has rallied nearly 40 percent since Relational and CalSTRS first disclosed their stake in November.

The investors believe the stock could rise to as much as $69 per share if the businesses were separated, which would eliminate misunderstandings of the assets by investors who specialize in the different sectors.

Timken has argued to the contrary, saying the loss of diversification benefits would largely offset any near-term valuation gain that might result from a separation of the businesses.

Timken's second and third-largest shareholders collectively own a 10.8 percent stake and are both affiliated with the company or its founding family, possibly making the activist campaign a challenge.

But the investors have enough shareholder support outside of the family to allow them to ultimately prevail, Whitworth said.

"We have had incoming calls into us, encouraging us and urging us to move forward and expressing support. Now we'll proactively go out and reach out to the shareholder base," he said. "We are confident that an overwhelming majority of public shareholders want a separation of the company and will support the proposal."

Several diversified conglomerates have decided to break up in recent years to focus on core businesses and streamline operations, often under pressure from activist investors.

Whitworth pressured industrial conglomerate ITT Corp (ITT.N) to split up its defense and water purifying businesses. Other companies that have pursued break-ups or major divestitures include Tyco International (TYC.N), Kraft Foods Inc (KRFT.O) and Fortune Brands (FBHS.N).

(Reporting by Soyoung Kim in New York; additional reporting by A. Ananthalakshmi in Bangalore and Michael Erman in New York; editing by Carol Bishopric)

©2013 Thomson Reuters.