If you sell CNC tooling, cutting fluids, metrology equipment, or industrial services, NAICS 3327 is one of the densest ICP clusters in US manufacturing — and one of the most underserved. There are more than 50,000 machine shops, turned-product facilities, and fastener manufacturers across the country, and the majority are small, private operations that are below the radar of HQ-centric B2B databases. That invisibility is your opportunity, if you have the facility-level data to work the territory.
NAICS 3327 is the US Census industry classification for Machine Shops; Turned Product; and Screw, Nut, and Bolt Manufacturing. It covers facilities that cut, grind, bore, and shape metal into precision parts using machine tools. Three six-digit sub-codes live inside it: 332710 (Machine Shops), 332721 (Precision Turned Product Manufacturing), and 332722 (Bolt, Nut, Screw, Rivet, and Washer Manufacturing). Together they account for more than 50,000 establishments across the United States.
What NAICS 3327 Covers
NAICS 3327 sits inside subsector 332 — Fabricated Metal Product Manufacturing, which itself lives under sector 33 — Manufacturing. The defining characteristic of 3327 is machining: these facilities remove material from metal stock (bar, rod, plate, casting, or forging) using lathes, mills, grinders, and multi-axis CNC machines. The output is precision metal parts — not raw shapes, not finished consumer goods, but intermediate components that feed into larger assemblies.
NAICS 332710 — Machine Shops
Census definition: Establishments primarily engaged in machining metal parts for others on a job-order or custom basis. Operations include turning, milling, boring, drilling, honing, grinding, and threading using precision machine tools.
This is the largest sub-code by establishment count. Machine shops range from one-person job shops to multi-shift contract manufacturers with 500+ employees. The typical shop takes a customer's print, programs its CNC machines, and delivers finished parts to spec.
Common products: Shafts, housings, brackets, hydraulic components, valve bodies, custom fasteners, tooling fixtures.
End markets: Automotive, oil and gas, defense, aerospace, industrial machinery, medical devices.
Example company types: Contract CNC machining centers, precision job shops, specialty grinding houses, aerospace machining subcontractors.
NAICS 332721 — Precision Turned Product Manufacturing
Census definition: Establishments primarily engaged in manufacturing automatic or semi-automatic screw machine products, and precision turned parts, bolts, nuts, screws, rivets, and washers made on screw machines.
Precision turned product shops run screw machines — high-speed, multi-spindle automatic lathes that produce turned parts from bar stock at volume. Where 332710 shops typically run short-to-medium runs on CNC machining centers, 332721 shops specialize in long runs of rotationally symmetric parts.
Common products: Turned shafts, pins, bushings, fittings, medical implants, hydraulic fittings, connector bodies, standoffs.
End markets: Aerospace, defense, automotive, medical, electronics, fluid power.
Key differentiator from 332710: It is the production method and volume, not the geometry. Precision turned product shops are defined by screw-machine operations; machine shops cover the broader universe of CNC machining.
NAICS 332722 — Bolt, Nut, Screw, Rivet, and Washer Manufacturing
Census definition: Establishments primarily engaged in manufacturing bolts, nuts, screws, rivets, and washers from purchased metal.
This sub-code covers fastener manufacturers — not distributors. Facilities here cold-head, hot-forge, or roll-thread rod or wire into standard and specialty fasteners at scale. Think structural bolts for bridge construction, aerospace-grade titanium fasteners, or custom locking nuts for heavy equipment.
Common products: Hex bolts, cap screws, flange nuts, rivets, washers, anchor bolts, specialty aerospace fasteners.
End markets: Construction, automotive, aerospace, defense, heavy equipment, rail, energy.
Well-known companies in this space: MW Industries (specialty springs and fasteners), Phillips Screw Company (drive-system licensing plus manufacturing), Illinois Tool Works fastener divisions, SPS Technologies (aerospace fasteners, a PCC subsidiary).
What Is NOT in NAICS 3327
Understanding the boundaries matters as much as understanding the definition.
| Process | Correct NAICS |
|---|---|
| Metal stamping (presses, dies) | 332300 (Metalwork) / 332116 |
| Metal forgings | 332111 (Iron and Steel Forgings) |
| Castings | 331511–331524 (Foundries) |
| Metal springs | 332613 |
| Wire drawing | 331420 |
| Fastener distribution (no mfg) | 423840 (Wholesale — Industrial Hardware) |
Distributors like Fastenal and Grainger are in wholesale trade (NAICS 423840), not 3327. Only companies that manufacture fasteners belong here.
Historical SIC Mapping
Before NAICS replaced the Standard Industrial Classification system in 1997, these activities were classified under:
| Old SIC Code | Description |
|---|---|
| 3462 | Iron and Steel Forgings (partially) |
| 3462 / 3544 | Special Industry Machinery (job shops for tools) |
| 3462 / 3599 | Industrial and Commercial Machinery, NEC |
| 3462 / 3462 | — |
| 3462 / 3562 | Ball and Roller Bearings |
| 3462 → 332710 | Machine Shops (SIC 3599 was the primary predecessor) |
| 3462 → 332721 | Screw Machine Products (SIC 3462 / 3544 → SIC 3460 / 3462) |
| SIC 3452 | Bolts, Nuts, Screws, Rivets, and Washers → 332722 |
| SIC 3599 | Industrial and Commercial Machinery, NEC (machine shops) → 332710 |
| SIC 3462 | Screw Machine Products and Bolts → 332721 / 332722 |
The main lineage: SIC 3462 and 3599 fed into the NAICS 3327 group. Researchers cross-referencing pre-1997 data should use SIC 3462 (screw products) and SIC 3599 (machine shops) as the primary ancestors.
Industry Scale
Establishment count: US Census County Business Patterns data puts the combined 3327 group at approximately 53,000–56,000 establishments nationally. Machine shops (332710) make up roughly 70% of that total — approximately 38,000 facilities. Precision turned product shops (332721) account for around 5,000–6,000 establishments, and fastener manufacturers (332722) are fewer in number but larger in average employment.
Employment: The 3327 group collectively employs an estimated 450,000–480,000 workers, making it one of the largest manufacturing subsectors by headcount in the fabricated metals cluster.
Geographic concentration: Machine shops cluster in the Midwest (Ohio, Michigan, Illinois, Wisconsin, Indiana), the South (Texas, Tennessee, North Carolina), and the Northeast (Pennsylvania, New York, Connecticut). Fastener manufacturing is disproportionately concentrated in Illinois (the Chicago-area fastener belt), Ohio, and California. California also has a dense concentration of aerospace-spec precision turned product shops.
End Markets Served
3327 facilities are upstream suppliers. Their output feeds into:
- Automotive — engine components, transmission parts, suspension hardware
- Aerospace and defense — airframe fasteners, precision turned hydraulic fittings, structural bolts
- Oil and gas / energy — valve bodies, wellhead components, custom fittings
- Industrial machinery — custom shafts, housings, fixtures
- Construction — structural bolts, anchor systems, heavy fasteners
- Medical devices — precision turned implants, surgical instrument components
Why NAICS 3327 Matters for Sales Teams
The 50,000+ establishments in NAICS 3327 represent one of the most attractive and underserved ICP clusters in US industrial sales. Here is why:
Who sells to them:
- CNC tooling vendors (cutting tools, inserts, drills, end mills) — every 332710 shop is a recurring buyer
- Coolant and metalworking fluids — machine shops consume significant volumes on repeating cycles
- Metrology and quality equipment (CMMs, gauges, surface roughness testers) — precision specs demand inspection
- Machine tool dealers (new and used CNC lathes, mills, machining centers)
- ERP and shop floor software vendors targeting small-to-mid-size job shops
- Tooling fixtures and workholding manufacturers
- Industrial gases (cutting, welding, heat treating adjacent)
The prospecting challenge: Most 3327 establishments are small, private, and not in ZoomInfo. The average machine shop has 10–40 employees. They do not have a press-release footprint. They are invisible to HQ-centric databases.
The opportunity: That invisibility is the gap. A territory seller covering the Midwest for a CNC tooling brand has thousands of machine shops in their zip codes. The shops exist. The plant-level data exists. Routing it into a sales workflow is the problem.
Facilities Finder indexes the machine-shop, turned-product, and fastener-manufacturing universe at the facility level — address, employee count, AI-enriched product and capability profile, and direct contacts. Territory reps describe what they sell to in plain English — "CNC machining," "precision turned hydraulic fittings," "structural bolt manufacturers" — layer a territory polygon or radius, and the built-in Facilities Finder CRM pipeline populates with matching accounts in minutes — each one a real plant address, not an HQ registration.
How to Find Machine Shops, Turned-Product, and Fastener Manufacturers in Your Territory
Facilities Finder does not ask you to memorize NAICS codes or drill into six-digit sub-classifications. Our AI indexes what each plant actually makes — 35,000+ industry classifications and 7 million+ products drawn from satellite imagery, map providers, company websites, EPA filings, permit records, and trade publications — so you describe what you're looking for in natural language, and the AI surfaces every facility that actually matches.
- Go to Facilities Finder and open the facility search.
- Type what you are looking for in plain English — "machine shops in Ohio," "precision turned product manufacturers within 150 miles of Houston," "aerospace fastener manufacturers with 100+ employees." Our AI extracts products, industries, and intent from the query, then ranks all 600,000+ indexed facilities by how well each one actually matches.
- Layer a territory filter on top — draw a polygon on the map, run a radius search from a central point, or filter by state or county.
- Narrow further by employee range, facility type, or specific capabilities (five-axis, multi-spindle, AS9100, ITAR-registered — whatever signals fit your ICP).
- Tier 1 accounts flow directly into the rep's pipeline inside the built-in Facilities Finder CRM — deals auto-create with the facility address, AI-generated industry and product classifications, and decision-maker contacts already attached. No CSV round-trip, no separate CRM to sync into.
You see every indexed facility in your area that actually makes what you sell to — not just the ones whose Census-assigned NAICS code happens to match. Semantic search across AI-enriched facility profiles, not keyword match against a classification bucket.
Beyond the NAICS Code: Why Classification Alone Isn't Enough for Industrial Sales
NAICS 3327 tells you what a facility is called in the Census system. It does not tell you what that facility actually makes, which customers it serves, or what it is capable of producing tomorrow.
Two shops can share the same NAICS 332710 classification and operate in completely different markets. One is a five-axis aerospace machining center producing titanium structural components for a defense prime — AS9100 certified, ITAR registered, running tolerances in the ten-thousandths. The other is a small job shop producing hobby-grade steel fasteners and bracket stock for general industrial use. Same six-digit code. Radically different buyers, capabilities, and sales conversations. A NAICS filter surfaces both. A sales rep cannot tell them apart from the code alone.
That is the gap Facilities Finder's AI was built to close. Our AI ingests billions of public signals — satellite imagery, map providers, company websites, EPA filings, permit records, trade publications — and extracts what actually matters: the products each facility produces, the capabilities it runs, the certifications it holds, and the industry contexts it serves. That enrichment produces 35,000+ AI-generated industry classifications and 7 million+ products indexed per facility — drawn from what plants actually produce, not from what a NAICS code was assigned to them by a Census surveyor. A search for "aerospace titanium machining" surfaces the right shops. A search for "precision turned hydraulic fittings near Houston" does the same. Semantic search across AI-enriched profiles — not keyword match against a classification bucket.
The NAICS code is your starting point. What Facilities Finder builds on top of it is what makes the data actionable for field sales.
Frequently Asked Questions
What NAICS code is a machine shop?
A machine shop's NAICS code is 332710. This covers establishments that machine metal parts on a job-order or custom basis using CNC lathes, mills, grinders, and other precision machine tools. The parent four-digit group is NAICS 3327.
What is the difference between 332710 and 332721?
NAICS 332710 (Machine Shops) covers a broad range of CNC machining operations — turning, milling, drilling, grinding — typically on a job-order basis with short-to-medium production runs. NAICS 332721 (Precision Turned Product Manufacturing) specifically covers facilities that use automatic or semi-automatic screw machines to produce high-volume rotationally symmetric turned parts from bar stock. The equipment and production economics differ. 332721 shops are set up for longer runs of standard turned geometries; 332710 shops handle greater variety.
Are fasteners in NAICS 3327?
Yes — but only fastener manufacturers. Bolt, nut, screw, rivet, and washer manufacturing is classified under NAICS 332722, which sits inside the 3327 group. Fastener distributors (companies that buy and resell without manufacturing) belong in wholesale trade under NAICS 423840 and are not part of the 3327 manufacturing cluster.
Is Fastenal in NAICS 3327?
No. Fastenal is a fastener distributor, not a manufacturer. It is classified under NAICS 423840 (Industrial and Personal Service Paper and Related Products, Wholesale) or more specifically the hardware wholesale codes. Companies like MW Industries, Phillips Screw Company, and SPS Technologies — which actually manufacture fasteners — are the 332722 representatives.
How many machine shops are in the United States?
Based on US Census County Business Patterns data, there are approximately 38,000–40,000 establishments classified under NAICS 332710 (Machine Shops). Adding precision turned product shops (332721) and fastener manufacturers (332722) brings the total NAICS 3327 group to approximately 53,000–56,000 establishments nationally.
See All NAICS 3327 Facilities in Your Region
The prospecting problem is straightforward: 50,000+ machine shops and fastener manufacturers across the US, the majority with fewer than 40 employees, and almost none of them indexed in ZoomInfo or Apollo.io. Your CRM shows nothing. A Google search surfaces the same five shops in your city. The accounts exist — the data to work them does not, in most tools.
Facilities Finder indexes 600,000+ US industrial facilities at the facility level, including the full machine-shop, turned-product, and fastener-manufacturing cluster that NAICS 3327 describes. Type what you sell to in plain English — "CNC machining," "precision turned hydraulic fittings," "aerospace fastener manufacturers" — draw your territory polygon or set a radius, and add an employee-range filter to prioritize by shop size. Every result includes the plant address, employee count, AI-enriched industry classifications and product profile, and direct contacts — so you can build a working call list for your region in minutes, not days. That is the structural advantage over any HQ-centric database: Facilities Finder indexes physical plant locations, with 95% US coverage across all 50 states.
25 million+ decision-maker contacts indexed at the location where they work.
Request access to see NAICS 3327 facilities in your territory →
This post is the template for our NAICS explainer series. To replicate for any four-digit NAICS code in the industrial cluster: swap the sub-codes, Census definitions, typical products, end markets, example company types, geographic concentration notes, and buyer-side ICP description. The FAQ, SIC mapping table, and CTA pattern remain constant.