Republicans on the House Ways and Means Committee, who might be called "the forgotten 13," are feeling squeezed as their panel begins overhauling the tax code.

They have at least as much doubt as their Democratic colleagues about curbing deductions and cutting rates. Some don't like it at all. But the chief proponent of doing so is their president.

"There is a reluctance on the part of any member of the president's party to get too far from the president's plan. On the other hand, it's been clear from the beginning there are a lot of Republicans skeptical about that plan," said Rep. Bill Frenzel (R-Minn.).

The panel got down to serious tax-writing last week, with the spotlight on the Democrats, who control both the committee and the full House. Administration officials have pinned their hopes for producing a House bill on panel chairman Dan Rostenkowski (D-Ill.) and his allies.

But sweating it out behind the locked wooden doors of 1100 Longworth Building are a baker's dozen Republicans whose support also will be needed for votes on key portions of tax overhaul. Already, they don't like the direction tax-writing is taking.

Being a minority, the Republicans have little control over the process. They are far outnumbered by the 23 Democrats on the panel. They worry that they could go out on a limb for a particular plan and then see it repudiated by President Reagan. And they are thoroughly disenchanted with the alternatives proposed by Rostenkowski.

"I don't know of a single member who has been brought on board by the Rostenkowski proposals , and there is a greater amount of discontent than there was with the president's proposal," said Rep. Bill Archer (R-Tex.).

Generally, overhauling the tax code has not been a partisan affair. Pressure from interest groups pushing for their tax breaks has put committee members in the trenches together, helping unify what one staffer called "fortress Ways and Means."

"A new member asked me the other day if the Ways and Means Committee had always been so unpopular. I said the committee's job has always been to say no," said Rep. Willis D. Gradison (R-Ohio).

Perhaps because taxes affect Americans so directly, regional and ideological concerns tend to outweigh party interests on Ways and Means. The coalitions that form around particular provisions of the tax code during the panel's closed-door sessions tend to be bipartisan.

For example, Democrats on the committee are working closely with Rep. Raymond J. McGrath (R-N.Y.) to defeat any limitation on the deduction for state and local taxes.

But partisanship pops up here and there. Last week committee Republicans proposed using the Reagan tax plan as the vehicle for tax-writing, rather than basing their work on the Rostenkowski proposals or the current tax code.

In making the motion, Republicans went against the advice of Treasury Secretary James A. Baker III, who wanted the Rostenkowski proposals used to avoid partisan bickering. They picked up only one Democratic vote, and lost.

Many Republicans share a view of the tax code and its purpose that differs from their Democratic colleagues. During weeks of hearings on the Reagan plan over the summer, Republicans voiced the lion's share of doubts on curbing depreciation deductions for business and curtailing tax credits for operations abroad.

It also was Republicans who, at the end of the hearing process, issued a list of principles for tax overhaul, some of which clashed with the Reagan proposal.

Republicans on and off the committee deny persistent rumors that they are drafting alternatives to the Reagan plan or to the Rostenkowski proposals. But they say they stand ready to bring up their own package if they do not like the direction Democrats are heading.

"We're not trying to write our own little deal," said House Minority Whip Trent Lott (R-Miss.). "But if the process gets out of control, there are a lot of things we could do. If the Democrats turn the president's bill into a liberal tax increase, we have options we would make use of."

Several House Republican leaders have doubts about tax revision. House Minority Leader Robert H. Michel (R-Ill.), who has said he would not vote for any of the proposals currently under consideration, is feeling pressure from heavy industries and labor unions in his district. In a meeting with Reagan last Wednesday, Michel, Lott and other leaders told the president there was little GOP support in the House for tax revision.

Ways and Means Republicans, under pressure from their chairman and their president, feel more responsibility to produce legislation than do their colleagues. Committee members were incensed when Rep. Jack Kemp (R-N.Y.), Lott and 35 other House Republicans sent Reagan a letter opposing some of the Rostenkowski proposals and asking that Reagan support retaining such costly tax preferences as a $2,000 personal exemption and a lower corporate tax rate. The committee members have asked Michel to keep such protests under control.

In trying to whip up public support for tax overhaul, Reagan seems to recognize the weaknesses among his fellow Republicans. Since his plan was introduced in late May, the president has made speeches in districts of four GOP Ways and Means members and only two Democrats. Thursday, he was in the Cincinnati district of Gradison, who supports tax overhaul.

Despite the push by the president, many GOP members remain skeptical, not just of the proposal but of the pressure from Reagan. Several members with long tenure on the panel recall a similar effort in 1970 by President Richard M. Nixon.

As Congress was debating how large a cost-of-living increase to grant Social Security recipients (in the days before those increases were granted automatically), Nixon asked committee members to hold the line at 5 percent although Democrats were pushing for a 10 percent increase. Despite the political pain, Republicans voted en masse in committee against the larger increase.

It eventually passed nonetheless, and Nixon not only signed the legislation but enclosed a note in millions of checks taking credit for the increase. Ways and Means Republicans were left with nothing but angry constituents.