Precision Fasteners CNC Machining: Nuts, Studs & Bolts Guide精密紧固件 CNC 加工：螺母、螺柱与螺栓指南

A Tier-1 aerospace supplier ordered 5,000 standard M6 hex nuts from a global catalog last quarter. Two out of every hundred failed go/no-go ring gauge inspection because the catalog vendor's thread pitch was at the high end of the tolerance band. Every failed nut cost the supplier $18 in assembly-line stoppage and paperwork. That is the world precision fasteners CNC machining was built to fix. When your application needs a thread held to a tighter tolerance than the catalog shelf can offer, when your material call-out rules out the standard zinc-plated carbon steel, when your plating spec bans hexavalent chromium, or when you need a shape no catalog has ever heard of — the answer is CNC. This guide walks through what we have learned machining custom fasteners for OEM aerospace, automotive, robotics, audio and consumer electronics customers across 23 years in Dongguan: six fastener families we produce, six materials that cover 95% of OEM call-outs, four thread standards (UNC / UNF / metric coarse / metric fine) and the tolerance class behind each, the full CNC process chain from bar stock to inspected part, seven tolerances that decide whether a fastener assembles cleanly or fails in the field, and five application scenarios with their material and tolerance targets. For the broader framework on how thread standards map to general tolerance, see our CNC tolerance guide. For the turning-vs-milling choice that frames every fastener job, see our CNC turning vs milling guide.

What are precision fasteners and why CNC

A precision fastener is any threaded or mechanical fastening component — nut, stud, bolt, standoff, threaded insert, washer — produced to a tolerance, material, or geometry specification tighter or different than what off-the-shelf catalog hardware can supply. The category covers everything from a 2 mm M1.6 brass standoff for a printed circuit board to a 200 mm M36 stainless threaded shaft for an offshore valve assembly.

Compared with off-the-shelf catalog fasteners, CNC machined fasteners deliver four wins:

1. Material choice beyond carbon steel — brass C360, stainless 303/304/316, aluminum 6061/7075, titanium, alloy steel 12L14/4140, PEEK and other engineering plastics. The catalog shelf has zinc-plated carbon steel in three sizes; CNC has every machinable alloy in any size up to 600 mm length.

2. Tighter thread tolerance — catalog threads sit at Class 2A / 6g for external / internal threads; CNC can hold Class 1A / 4h for safety-critical aerospace or Class 3A / 5g for precision assemblies where thread stack-up cannot drift.

3. Geometry freedom — square nuts, hex with through-holes, captive standoffs, knurled thumb screws, custom anti-vibration profiles. None of these exist in a catalog.

4. Lot traceability and certification — every CNC fastener ships with a material cert, dimensional inspection report, and (where required) a PPAP or First Article Inspection document. Catalog parts ship with whatever the vendor has on the pallet.

That is why aerospace, automotive, robotics, medical, premium audio, and prosumer electronics have all moved to CNC machined fasteners for anything that is safety-critical, brand-visible, or sized outside the catalog shelf. For the engineering detail on the CNC turning process that produces most of these parts, our CNC turning vs milling guide covers when a turned vs milled fastener makes sense.

6 common fastener types we CNC machine

Fasteners come in many shapes, but the production floor sees the same six over and over. Each has a CNC sweet spot.

1. Hex nuts and square nuts

The default fastener. A hex nut is a 6-sided block with a tapped through-hole, produced on a CNC lathe from round bar stock. Hex nuts account for roughly 45% of our fastener volume. Standard call-outs are M3 to M24, 1/4"-20 to 1"-8 UNC, and imperial BA / BSF / BSW for legacy aerospace. Square nuts are the same idea with 4 sides, used where wrench access is tight and torque resistance matters (marine fittings, vintage motorcycle restorations). For premium consumer hardware, a hex nut machined from C360 brass and polished is a brand signature — see our audio knob guide for the wider context on brass turning.

2. Threaded studs and double-ended studs

A stud is a cylindrical rod threaded on one or both ends, used where one side screws into a tapped blind hole and the other side accepts a nut. We produce studs from M2 to M20, lengths 10 mm to 600 mm, in stainless 303 / 304 / 316, alloy steel, brass, and titanium. Double-ended studs (threaded both ends, plain in the middle) are the dominant fastener for flange joints in process piping and for engine mounting brackets in automotive — for the engineering detail on IATF 16949 production discipline, our IATF 16949 CNC guide covers the certification framework.

3. Cap screws and socket head cap screws (SHCS)

A cap screw is a hex or socket-head bolt with a fully machined head, produced on a CNC lathe (for the shank and threads) then transferred to a small CNC mill (for the hex socket). SHCS are the dominant fastener for precision assemblies — robotics joint covers, drone frame joints, audio equipment chassis, 3C electronics housings. The head-to-shank concentricity matters: a 0.05 mm runout will make the screw wobble in a driver and strip the socket under torque. We hold 0.03 mm concentricity on SHCS from M3 to M12.

4. Standoffs and spacers

A standoff is a hex or round tube threaded on both ends, used to separate two parallel surfaces (a PCB from a chassis, a heat sink from a logic board). Standoffs dominate the 3C electronics industry — every smartphone, laptop, and wearable has 4 to 12 of them. The CNC challenge: thread both ends concentric within 0.03 mm and hold length within ±0.05 mm. We produce standoffs from M2 to M8, lengths 3 mm to 50 mm, in brass, aluminum, stainless, and (for medical and aerospace) PEEK.

5. Threaded inserts and helical inserts

A threaded insert is a bushing with internal threads, pressed or molded into a softer parent material (plastic, die-cast zinc, magnesium, wood). The most common are helical coil inserts (Helicoil brand and equivalents), which we machine on multi-spindle CNC lathes from 304 stainless wire. Less common but growing: brass knurled inserts for plastic injection molding, where the knurl provides pull-out resistance.

6. Custom washers, sealing rings, and specialty shapes

The catch-all category: a shoulder washer with a custom ID/OD/thickness, a sealing ring with a rubber insert groove, a captive thumb screw with a knurled head and a through-hole for safety wire, a brand-marked thumb nut with the company logo engraved on the top face. Every "we need a fastener that does not exist in the catalog" job ends up here. Our DFM analysis guide covers the 5 design changes that cut custom fastener cost 20–40% with no loss of function.

Material selection: brass, stainless, aluminum, alloy steel

The wrong alloy wastes cycle time, ruins the plating line, or fails in service. Six materials cover 95% of OEM precision fastener call-outs.

1. Brass C360 — the free-machining default for small fasteners

C360 brass is the workhorse for small-to-medium brass turned parts fasteners — hex nuts, standoffs, knurled thumb screws, decorative nuts on premium audio and consumer hardware. It machines 3× faster than mild steel, takes a mirror polish, and holds tight thread tolerances without distortion. Density 8.5 g/cm³, tensile 400 MPa. Use it when you need machinability, a brand-quality finish, and electrical conductivity (the third property matters for grounding lugs and EMI hardware). For the broader brass behavior under CNC, our CNC turning vs milling guide covers machinability ratings.

2. Stainless steel 303 — the free-machining stainless

303 stainless is the sulfurized variant of 304, designed specifically for high-volume screw machine work. It machines at 80% the cycle time of 304, produces small broken chips (not the long stringers of 304), and accepts stainless steel threaded fasteners to Class 2A / 6g without difficulty. The trade-off: 303 has slightly lower corrosion resistance than 304 (the sulfur inclusions create pitting sites), so we steer 303 toward indoor industrial stainless steel threaded fasteners and 304 toward outdoor or marine applications.

3. Stainless steel 304 and 316 — corrosion resistance

304 stainless is the workhorse for outdoor and mildly corrosive environments — outdoor audio, kitchen equipment, marine-adjacent hardware. 316 stainless adds 2–3% molybdenum for chloride resistance — the right answer for marine, medical, and chemical-exposure fasteners. Both run 25–35% longer cycle times than 303 because they work-harden during cutting. Thread rolling (vs thread cutting) is preferred for both to avoid work-hardening the surface and risking stress corrosion cracking later. For the broader stainless behavior under CNC, our stainless steel CNC guide covers the full grade matrix.

4. Aluminum 6061 and 7075 — lightweight

6061-T6 and 7075-T6 are the right answer when weight matters more than strength — drone frames, robotics links, aerospace secondary structure. 6061 is the default (density 2.70 g/cm³, tensile 310 MPa); 7075 is for high-stress joints (density 2.81 g/cm³, tensile 570 MPa, yield 503 MPa). Both accept threads to Class 2A / 6g without difficulty, but both also require a thread-locking compound or a stainless helical insert in a tapped aluminum hole, because aluminum threads strip under repeated assembly. For the broader aluminum behavior under CNC, our aluminum CNC guide covers the full grade matrix.

5. Alloy steel 12L14 and 4140 — high strength, heat-treatable

12L14 is the standard leaded steel for low-strength fasteners (grade 2 / grade 5), and it is the most economical choice for indoor industrial brass turned parts-equivalent steel fasteners where corrosion is not a concern. 4140 is the standard alloy steel for high-strength fasteners that need to be heat-treated to grade 8 / grade 10 / grade 12 / ASTM A574. 4140 starts as a rough-turned blank, then is heat-treated (quench + temper) to the specified hardness, then finish-ground on the threads to hold Class 2A / 6g after the heat-treatment distortion. For the heat-treatment engineering detail, our heat treated CNC parts guide covers the distortion control techniques.

6. Titanium grade 5 (Ti-6Al-4V) and engineering plastics

For aerospace and medical fasteners where weight or biocompatibility is critical, titanium grade 5 (Ti-6Al-4V) is the default — density 4.43 g/cm³, tensile 895 MPa, fully biocompatible. Cycle time is 4–5× the time for stainless because titanium is gummy and work-hardens aggressively. Engineering plastics (PEEK, PPS, Torlon) are used where electrical insulation or chemical resistance matters — transformer bolts, chemical plant fittings, MRI room fasteners (where metallic fasteners are forbidden). For the broader titanium and PEEK behavior under CNC, our PEEK CNC guide covers the engineering plastic framework.

Thread standards and tolerance classes

Threads are where fasteners either assemble cleanly or fail in service. The choice of standard and tolerance class is driven by the assembly stack-up — and mis-specifying it is the single most common cause of fastener callbacks.

1. Unified National Coarse (UNC) and Unified National Fine (UNF)

The dominant inch-based standard. UNC (e.g. 1/4"-20) is for general-purpose assembly — automotive frames, machinery enclosures, structural joints. UNF (e.g. 1/4"-28) is for thin-wall assemblies and where vibration loosening is a concern — aerospace secondary structure, robotics joints, automotive engine accessories. UNF gives finer pitch (more threads per inch = more holding power per unit length) at the cost of slightly slower machining and slightly higher tap breakage risk.

2. Metric coarse and metric fine

The dominant global standard. Metric coarse (e.g. M6×1.0) is the general-purpose equivalent of UNC. Metric fine (e.g. M6×0.75) is the equivalent of UNF, used in the same applications. Most global OEMs (automotive, consumer electronics, industrial machinery) default to metric coarse for ease of sourcing.

3. Thread tolerance classes: 1A / 2A / 3A (external) and 1B / 2B / 3B (internal)

The A/B suffix means external (A) / internal (B) threads. The number is the tolerance class — lower number is tighter. Class 1A / 1B is the loose fit, used where assembly must slide freely (hinge pins, adjustment screws). Class 2A / 2B is the standard catalog fit — what you get off the shelf. Class 3A / 3B is the precision fit — the right answer for safety-critical aerospace, robotics bearing preload, and high-cycle assemblies where thread stack-up cannot drift.

4. Pitch diameter and its measurement

The single tolerance that matters most is pitch diameter — the diameter of an imaginary cylinder that just touches the thread crests and roots. Pitch diameter is checked with Go / No-Go ring gauges (for external threads) or plug gauges (for internal threads). The gauge will pass a thread that is within tolerance and reject one that is out — even by 0.01 mm. For an M6×1.0 external thread at Class 6g, the pitch diameter window is 5.350–5.412 mm. For the engineering framework behind these numbers, our CNC tolerance guide covers ISO 2768 and GD&T.

CNC process chain for fasteners

A clean production flow is the difference between a 7-day lead time and a 25-day lead time. Here is the process we run for a typical M6×1.0 hex nut in C360 brass.

Step 1: Bar stock selection and cutoff

We stock C360 brass round bar in diameters from 2 mm to 60 mm, 303 / 304 / 316 stainless round bar from 3 mm to 50 mm, 12L14 and 4140 round bar from 3 mm to 80 mm, 6061 / 7075 aluminum round bar from 4 mm to 100 mm. The bar saw cuts blanks to length + 0.5 mm machining allowance per face. For volume orders, we run an automatic bar feeder on a CNC lathe — no operator intervention between parts. For prototype or low-volume orders, blanks are saw-cut in batches.

Step 2: CNC lathe turning

The CNC lathe turns the OD, faces both ends, drills any through-hole or blind hole, and chamfers all edges. For a hex nut, the OD is turned round first (slightly oversized), then a secondary operation on a CNC mill or a CNC lathe with live tooling forms the hex flats. For a stud or cap screw, the OD is turned to the major thread diameter (slightly oversized for the thread rolling or cutting step), and the head (if any) is faced and grooved.

Step 3: Thread rolling or thread cutting

For external threads (studs, cap screws), we default to thread rolling on cylindrical workpieces — the bar is passed between two hardened dies that press the thread profile into the surface. Thread rolling is faster, produces a stronger thread (the rolling work-hardens the surface), and uses less material than cutting. For internal threads (nuts, tapped holes, inserts), we default to thread cutting with a tap or a thread mill. For the engineering detail on which threads should be cut vs rolled, our CNC tolerance guide covers thread specification in ISO 6410 / 6411.

Step 4: Secondary milling (hex flats, drive sockets, knurls)

For a hex nut, a SHCS, or a knurled thumb screw, the part is transferred from the lathe to a small CNC mill for the flats / socket / knurl pattern. Concentricity from lathe to mill is held by a precision collet or fixture. For a standoff or a threaded insert, both ends may be threaded in a single lathe setup with live tooling — no secondary operation needed.

Step 5: Heat treatment (if specified)

For alloy steel fasteners above grade 5 (e.g. grade 8, grade 10, grade 12, ASTM A574), the parts are heat-treated (quench + temper) to the specified hardness. Heat treatment adds 3–5 days and produces some distortion — that is why we finish-grind the threads after heat treatment for grade 8 and above. For the heat-treatment engineering detail, our heat treated CNC parts guide covers the 5 processes (quench + temper, carburizing, induction, precipitation, nitriding) and 4 distortion control techniques.

Step 6: Surface finishing (plating, anodizing, passivation)

Surface finishing depends on the material and the application. Stainless steel fasteners for outdoor use get passivation (nitric acid or citric acid bath that removes free iron and promotes the chromium oxide layer). Carbon steel fasteners get zinc plating (clear, yellow, or black chromate) for corrosion resistance, or zinc-nickel plating for automotive underbody applications. Aluminum fasteners get clear or black anodizing for corrosion resistance and brand color. Brass fasteners are usually left natural and polished. For the engineering detail on aluminum anodizing, our anodizing aluminum guide covers the layer growth and color control.

Step 7: Inspection, gauge certification, and packaging

Every CNC fastener is dimensionally checked against the drawing. Threads are checked with Go / No-Go gauges (ring gauge for external, plug gauge for internal). Critical dimensions (length, head-shank concentricity, hex width across flats) are checked with calibrated calipers, micrometers, and pin gauges. For aerospace and automotive PPAP orders, every batch ships with a First Article Inspection report, material certificate, and (for heat-treated parts) a hardness test report. For the framework on supplier qualification, our choosing CNC supplier guide covers the audit checklist.

7 critical tolerances for precision fasteners

Tolerances are where precision fasteners earn their name. Get them wrong and the fastener does not assemble, the joint fails, or the audit fails. These seven are the ones that matter.

1. Pitch diameter (thread Ø): ±0.04 mm (Class 6g)

The pitch diameter is the single tolerance that matters most. For an M6×1.0 external thread at Class 6g, the pitch diameter window is 5.350–5.412 mm — a 0.062 mm wide band. For tighter Class 4h, the band shrinks to 0.035 mm. Out-of-spec pitch diameter will fail the Go / No-Go gauge inspection at the receiving dock. We hold ±0.04 mm on most Class 6g threads and ±0.02 mm on Class 4h aerospace threads.

2. Major diameter (OD): ±0.05 mm

The major diameter (outer crest of the thread) is checked less often than pitch diameter, but it matters for assembled fit. For an M6 external thread, the major diameter is 5.92–6.00 mm at Class 6g. Out-of-spec major diameter will not seat properly in a counterbored hole.

3. Minor diameter (root Ø): ±0.10 mm

The minor diameter (root of the thread) is the loosest tolerance because it does not contact the mating thread. But too-small minor diameter weakens the thread; too-large minor diameter does not allow the rolling die to fully form. We hold ±0.10 mm.

4. Length: ±0.05 mm

For a stud, standoff, or cap screw, length is held to ±0.05 mm. Out-of-spec length causes the joint to either bottom out before clamping or fail to clamp at all. For assembled stacks with multiple fasteners, length tolerance drives stack-up accuracy.

5. Across-flats (hex width): ±0.05 mm

For a hex nut or a hex head bolt, the across-flats dimension (the dimension the wrench grabs) is held to ±0.05 mm. Out-of-spec across-flats means the wrench slips, rounds the corners, and the fastener cannot be torqued. This is the failure mode most often seen in field returns for "wrench won't grip the nut".

6. Head-to-shank concentricity: 0.03 mm

For a cap screw or SHCS, the hex socket (or external hex head) must be concentric to the shank within 0.03 mm. Out-of-concentric heads make the driver wobble, strip the socket, and ruin the fastener. We check head-to-shank concentricity on every batch with a dial indicator on the lathe.

7. Surface roughness on thread flank: Ra 1.6 μm

The thread flank (the load-bearing surface) should have a surface roughness of Ra 1.6 μm or smoother. Rougher flanks cause friction during assembly, scatter in torque-tension relationship, and risk galling in stainless steel threads. We check with a profilometer on first article and on every 100th piece in production.

For the broader tolerance framework — ISO 2768 medium vs fine, GD&T callouts, statistical tolerancing — our CNC tolerance guide is the comprehensive reference.

5 application scenarios with different material and tolerance targets

The right material and tolerance depend entirely on the application. Five scenarios cover the OEM spectrum.

Aerospace

Material: titanium grade 5 (Ti-6Al-4V) or 17-4 PH stainless. Tolerance: Class 4h / 4h pitch diameter (tighter than catalog), ±0.02 mm length. Surface: passivation per AMS 2700. Traceability: full PPAP, FAI, material cert, and process cert per AS9100. For the IATF 16949 / AS9100 framework, our IATF 16949 CNC guide covers the certification scope.

Automotive

Material: 10B21 / 12L14 / 4140 alloy steel, depending on grade (2, 5, 8, 10). Tolerance: Class 6g / 6H pitch diameter (standard), ±0.05 mm length. Surface: zinc-nickel plating per automotive spec, or Dacromet / Geomet for underbody. Traceability: PPAP, FAI, material cert per IATF 16949. For the automotive bracket and engine component context, our IATF 16949 CNC guide covers the certification framework.

Robotics and drones

Material: 7075-T6 aluminum (lightweight) or 303 stainless (high-cycle). Tolerance: Class 6g / 6H pitch diameter, ±0.05 mm length. Surface: clear anodize (aluminum) or passivation (stainless). Traceability: FAI and material cert. For the broader robotics context, our robot joint CNC guide covers the bearing-seat tolerance discipline that drives fastener selection in robotic joints.

Audio equipment

Material: C360 brass (decorative / grounding), 6061-T6 aluminum (chassis). Tolerance: Class 6g / 6H pitch diameter, ±0.05 mm length. Surface: mirror polish + clear coat (brass), brushed + black anodize (aluminum). Traceability: cosmetic inspection and dimensional cert. For the audio chassis context, our amplifier front panel CNC guide covers the finishing framework.

Consumer electronics and 3C

Material: C360 brass (premium standoffs), 6061-T6 aluminum (chassis fasteners), PEEK (insulators). Tolerance: Class 6g / 6H pitch diameter, ±0.03 mm length (tight for stacked PCB assemblies). Surface: natural (brass), clear anodize (aluminum), natural (PEEK). Traceability: cosmetic inspection and dimensional cert.

Why choose a Dongguan CNC shop for fasteners

For OEM buyers specifying precision fasteners, the question is rarely "can anyone make this" — it is "who can make this at the right cost, with the right material cert, on the right timeline". A 23-year Dongguan shop with 200+ CNC machines and three ISO certifications has four structural advantages on fasteners specifically.

First, scale. Fastener production rewards scale: every 10,000 pieces brings the per-piece cost down. A shop that runs 50,000 fasteners per month across automotive, robotics, and consumer electronics amortizes its setup time over more parts than a job shop running 1,000. Second, vertical integration. The same factory that turns the nut also taps the thread, mills the hex flats, heat-treats the alloy steel, plates the finish, and inspects with calibrated gauges. No sub-supplier handoffs, no documentation loss. Third, material cert and traceability. IATF 16949 + ISO 9001 + ISO 13485 force a discipline on documentation — every batch ships with a material certificate, dimensional inspection report, and (where required) PPAP / FAI paperwork. Fourth, DFM responsiveness. Fasteners are simple enough that engineers often spec them last and forget about them — and then pay 30% more than they needed to because the catalog call-out was over-specified. A 23-year shop will review your fastener spec against your assembly stack-up and propose a tighter or looser tolerance as appropriate. For the framework on supplier qualification, our choosing CNC supplier guide covers the 7-point checklist.

For aerospace, automotive, robotics, audio, and 3C electronics fasteners in brass, stainless, aluminum, alloy steel, titanium, and PEEK, we hold ±0.01 mm dimensional and ship Go / No-Go gauge certification with every batch. ISO 9001 + IATF 16949 + ISO 13485. Send your drawing and assembly stack-up — DFM review included, firm quote within 24 hours.

FAQs about precision fasteners CNC machining

What is the typical MOQ for custom CNC machined fasteners?

For most custom nuts, studs, and bolts, the practical MOQ at a CNC job shop is 100–500 pieces for the first run. Below 100 pieces, the per-piece cost rises because the setup time (program prove-out, tooling setup, first article inspection) is amortized over fewer parts. For brass and aluminum fasteners, we run prototypes as low as 20 pieces; for stainless and titanium, the minimum is typically 100 pieces because of the material order minimums.

Can you match a specific thread class tighter than the catalog?

Yes. We routinely produce external threads at Class 1A (looser than catalog) and Class 3A or 4h (tighter than catalog). The tighter the class, the more careful the thread rolling or thread cutting setup must be — and the more we recommend thread grinding after heat treatment for grade 8 / 10 / 12 alloy steel. Specify the tolerance class on the drawing as a note (e.g. "Thread per ISO 6410-1, Class 6g") and we will hold it.

What is the difference between thread rolling and thread cutting?

Thread rolling presses the thread profile into the surface between two hardened dies — no material is removed, the grain flow follows the thread contour, and the rolled thread is 30% stronger than a cut thread. Thread cutting removes material with a tap or a thread mill — slower, weaker, but possible on materials too hard to roll (above ~HRC 40) or on parts with features that cannot be reached by a rolling die. Default to rolling for ductile materials below HRC 35.

Should I specify brass, stainless, or alloy steel for a custom nut?

Material choice depends on three factors: corrosion environment (stainless or brass for outdoor / marine; alloy steel for indoor), strength requirement (alloy steel heat-treated for high strength; brass or aluminum for low strength), and electrical conductivity (brass for grounding; the others for non-conductive applications). For a generic "looks like a normal nut" application, C360 brass is the easiest to machine and the cheapest for small sizes.

How do you hold ±0.01 mm tolerances on a 1 mm M1.6 brass standoff?

We hold the standoff concentricity on a single CNC lathe with live tooling (both ends threaded in the same setup), measure with a pin gauge and a calibrated optical comparator, and document every batch. For M1.6 brass standoffs, the thread pitch diameter window is 1.567–1.621 mm at Class 6g — a 0.054 mm band. Our typical production holds ±0.02 mm on the pitch diameter for these small brass parts.

What is the typical lead time for a 1,000-piece custom fastener run?

For C360 brass or 6061 aluminum fasteners in standard thread classes, 1,000-piece lead time at a Dongguan CNC shop is typically 10–15 working days. For 4140 alloy steel that requires heat treatment, add 3–5 days. For titanium grade 5, add 5–7 days because the cycle time is longer and the material is more expensive. For prototypes (50–100 pieces), expect 5–8 days for brass and aluminum, 8–12 days for stainless and alloy steel.

Conclusion

Precision fasteners CNC machining is not exotic — it is the boring, disciplined work of turning, tapping, rolling, and inspecting threaded parts to tighter tolerances than a catalog can supply. Pick the material for the environment (brass or 303 SS for indoor, 304 or 316 SS for outdoor / marine, aluminum for lightweight, alloy steel for high strength, titanium for aerospace), specify the thread class for the stack-up (Class 2A / 6g for general, Class 1A / 4h for loose fit, Class 3A / 4h for safety-critical), default to thread rolling over thread cutting for ductile materials, hold the seven tolerances (pitch Ø ±0.04 mm, major Ø ±0.05 mm, minor Ø ±0.10 mm, length ±0.05 mm, across-flats ±0.05 mm, head-shank concentricity 0.03 mm, thread flank Ra 1.6 μm), and ship with Go / No-Go gauge certification. If you are ready to source custom fasteners, send your drawing and assembly stack-up to our team. Request a quote today and let our 23 years of CNC turning experience work for your brand.

Need custom CNC machined fasteners? Send your drawing and assembly stack-up — DFM review included, firm quote within 24 hours.