HTS 8433.20.00Harvesting or threshing machinery, including straw or fodder balers; grass or hay mowers; machines for cleaning, sorting or grading eggs, fruit or other agricultural produce, other than machinery of heading 8437; parts thereof:Other mowers, including cutter bars for tractor mounting

The steel, aluminum and copper tariff doesn't apply to “Articles provided for in subdivision (c) of U.S. note 16 to this subchapter that do not contain any aluminum, steel, or copper” (HTS 9903.82.01).

The steel, aluminum and copper tariff doesn't apply to “Except for articles classifiable in chapters 72, 73, 74 or 76, articles where the weight of the applicable metal is less than 15 percent of the weight of the imported article” (HTS 9903.82.03).

No forced-labor tariff here: products covered by the steel, aluminum and copper tariff (HTS 9903.82.10) are exempt from it.

The steel, aluminum and copper tariff instead is 10% in place of the regular duty where this applies: “For derivative articles provided for in subdivisions (c)(ii), (vi), and (ix), at least 85 percent of the aluminum content of the article must be composed of aluminum that was smelted and cast in the United States. For derivative articles provided for in subdivisions (c)(iv), (vii), (x) and (xi), at least 85 percent of the steel content of the article must be composed of steel that was melted and poured in the United States. For articles provided for in subdivision (c)(viii), at least 85 percent of the copper content of the article must be composed of copper that was smelt and cast in the United States. These requirements are cumulative such that a derivative article in more than one subdivision must satisfy each requirement” (HTS 9903.82.07).