Section 301 Tariff on Machined Parts: HTS Codes, Rates, and the Vietnam Alternative (2026)

Last updated: June 2026

The section 301 tariff on machined parts imported from China is not a temporary condition — it is a line item on every China-origin invoice, running 25% to 145% depending on HTS classification. If you source CNC machined parts from China, this guide breaks down which HTS codes apply, what the actual landed cost exposure looks like in 2026, and why procurement teams are moving to Vietnam-origin parts to eliminate the tariff entirely.

What Section 301 Is — and Why It Still Applies in 2026

Section 301 of the Trade Act of 1974 authorizes the US Trade Representative (USTR) to impose tariffs in response to trade practices deemed unfair. The current tariff schedule against Chinese goods — initiated in 2018–2019 under the Trump administration — covers roughly $370 billion in annual imports across four “lists.” In 2025–2026, these tariffs were not only kept in place but selectively increased on categories including semiconductors, EVs, and industrial machinery.

For procurement teams buying machined metal components, the Section 301 tariff — machined parts from China sitting at 25% baseline — is not a future risk. The base rate across most categories is 25%. On specific subsets — particularly tooling components and some precision assemblies — the rate reaches 145% when stacked with pre-existing MFN duties.

Key HTS Codes for CNC Machined Parts — Section 301 Rates

Not every machined component falls under the same code. The HTS chapter and heading determine the applicable rate. Below are the most relevant codes for buyers sourcing precision-machined components from China.

Note: HTS classifications are determined by CBP at entry. Final duty rates depend on the specific tariff schedule in effect at time of import. Consult a licensed customs broker for binding classification decisions. Rates above reflect the 2026 schedule as published by USTR.

What the Tariff Actually Costs: A Procurement Calculation

Procurement teams often underestimate Section 301 exposure because it shows up as a customs line item rather than a supplier price increase. The actual calculation is straightforward.

Example: Aluminum CNC Housing — HTS 7616.99

In this scenario, the China supplier’s ex-works price is 12.5% cheaper — but the Section 301 tariff on machined parts reverses the advantage entirely. The procurement team ends up paying $649 more per 100-piece order. On a 12-month rolling program at $50k/month, that is $7,800 in tariff cost paid directly to CBP with zero supplier value in return.

Rules of Origin: When Does “Made in Vietnam” Actually Count?

US Customs and Border Protection applies substantial transformation rules to determine country of origin. For machined parts, the standard is whether the manufacturing process in Vietnam constitutes substantial transformation — not just assembly or labeling.

For CNC machined components produced at VNcontX: raw billet or bar stock (aluminum, steel, stainless, titanium) is procured from Vietnamese or Korean/Japanese mills, then machined to drawing in our Bình Chánh facility. The transformation from raw material to finished, dimensionally verified part clearly constitutes substantial transformation under CBP standards — meaning the Section 301 tariff on machined parts does not apply, and the resulting certificate of origin classifies the part as Vietnamese-origin.

VNcontX provides a standard documentation package with every shipment: material mill certificate, manufacturing process summary (drawing → programming → machining → CMM inspection → shipment), and a certificate of origin. This documentation is sufficient for most standard CBP entry requirements and supports clean audit trails if CBP requests verification.

Section 301 in 2026: What Has Changed

The tariff schedule has evolved since 2018. Key changes relevant to machined parts buyers in 2026:

Rates on industrial machinery and parts increased in 2025

USTR’s May 2024 review resulted in rate increases on specific categories effective 2025. Semiconductor-related machined components and certain specialty alloy parts saw increases from 25% to 50%. The Section 301 tariff on standard machined parts — aluminum and steel components under 8466, 8483, and 7616 — remains at 25%, but policy risk for further escalation is real.

Exclusion process remains limited

The Section 301 exclusion process — which previously allowed importers to petition USTR for product-specific relief — has been largely closed for new filings since 2021. Existing exclusions for machined parts have expired. As of 2026, there is no active exclusion pathway for standard CNC machined aluminum or steel components. Buyers cannot rely on an exclusion to recover tariff costs.

No sunset date

Section 301 tariffs do not have a statutory expiration. They require active USTR action to remove. With the current US-China trade environment, procurement teams modeling a 3–5 year horizon should treat the 25% rate as a baseline, not a temporary condition.

Vietnam as a Section 301-Exempt Sourcing Destination

Vietnam’s position as a contract manufacturing hub for US buyers grew significantly post-2018 precisely because it sits outside the Section 301 schedule. Several factors make it a viable alternative to China for machined components — not just a tariff workaround:

Manufacturing capability

HCMC and the surrounding industrial zones house a dense supplier base for CNC machining, sheet metal, and injection molding. Equipment levels — 5-axis machining centers, CMM inspection, EDM — are comparable to South China factories at equivalent price points. VNcontX runs DMG Mori 5-axis and Mazak QT turning centers, targeting tolerances of ±0.005mm standard and ±0.003mm precision, with Zeiss Contura CMM inspection on every order. For high-specification programs including aerospace machined components, the same tolerance and documentation stack applies.

Logistics position

Cat Lai Port, one of Southeast Asia’s highest-throughput container ports, is 20km from our facility. Air freight to LAX or SFO runs 2–3 days. West Coast sea freight: 18–22 days. These are not materially different from South China ports — and in some lane comparisons, HCMC to US West Coast is faster than Guangzhou or Shenzhen.

Trade agreements

Beyond the absence of Section 301 exposure, Vietnamese-origin goods benefit from EVFTA for EU buyers (reduced or zero duty on qualifying manufactured goods) and AANZFTA for Australian buyers (preferential rates). A supply chain restructured around Vietnam-origin parts eliminates tariff exposure across all three major markets simultaneously.

Moving Machined Parts Supply from China to Vietnam: Practical Considerations

Switching contract manufacturers mid-program is not trivial. For teams managing active Section 301 tariff exposure on machined parts, the business case is clear — see the total cost of ownership breakdown beyond tariffs for the full 7-component model — but execution questions are real.

Will the new supplier hold my tolerances?

Will the new supplier hold my tolerances?

This is the right question. Tolerance capability needs to be verified against your drawing stack, not assumed. VNcontX provides first article inspection (FAI) with CMM report on 100% of orders — the data package lets you verify against your GD&T callouts before committing to production volume. Lead time for FAI samples: 3–5 days expedited, 7–12 days standard.

How do I manage a parallel supplier during transition?

Most teams run a split-PO strategy: move lower-criticality parts or new programs to the Vietnam supplier first, maintain the China supplier on existing high-volume programs until FAI data is established. This reduces transition risk and gives your team time to evaluate quality against your actual parts, not generic capability claims.

What about tooling and fixtures held at the China supplier?

Check your current contract. In many China manufacturing arrangements, tooling ownership is ambiguous or de facto held by the supplier. When moving to VNcontX, we produce new tooling against your drawings — tool steel is specified in the quote, and mold/fixture ownership is contractually assigned to you. Transfer of tooling from existing suppliers is a separate logistics matter; we do not inherit it.

Documentation for CBP — what do I need to keep on file?

Maintain: purchase orders with Vietnam-origin supplier, supplier invoices showing Vietnam address, certificate of origin, material mill certificates, and shipping documentation (bill of lading showing loading port in Vietnam). For high-value programs, a supplier audit or process description document strengthens your position if CBP requests substantiation of country-of-origin claims.

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