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Choose us as your stainless steel CNC machining manufacturer, you can rest assured. We use different processes combined with CNC machining to meet your needs. Available in a variety of stainless steel materials, strict quality control processes are carefully monitored at each step to ensure stainless steel CNC parts meet the highest industry standards for performance and durability.
Product Specification:
VMT provides custom CNC machining and zinc plating coordination for steel and iron components made to your drawings. From DFM review and CNC turning or milling to plating requirements and final inspection, we help control critical dimensions, threads, mating surfaces and cosmetic requirements after finishing—not only before plating.
A machined part can meet drawing dimensions before plating but still create assembly problems after zinc is added. VMT reviews machining and finishing requirements together so critical features can be controlled according to the finished-part condition.
Zinc buildup can change internal and external thread fit. Thread requirements are reviewed before machining so additional control, masking or post-plating gauge inspection can be considered.
VMT Control: Thread + plating reviewPlating on internal surfaces can reduce bore size and affect pins, bearings and mating components. Critical holes are reviewed against required final dimensions.
VMT Control: Final bore requirementWhen machining tolerance and coating thickness both affect fit, the complete tolerance stack must be considered before production.
VMT Control: Functional fit reviewBearing seats, sealing faces, locating surfaces or electrical contact areas may require controlled plating or masking.
VMT Control: Masking / no-plate zonesVisible surfaces and acceptable contact areas should be defined before finishing so appearance requirements can be coordinated with the plating process.
VMT Control: Cosmetic acceptanceCoating thickness, passivation, appearance and testing requirements should be reviewed according to the drawing and application rather than assumed.
VMT Control: Specification reviewFor zinc-plated CNC parts, machinability is only one part of the engineering review. VMT also evaluates how finishing may influence functional dimensions, assembly and inspection so potential problems can be addressed before machining starts.
Thread functionality is reviewed against the final plated condition, including fit, exposure and inspection requirements.
Critical internal diameters used for bearings, pins or mating parts are reviewed for possible dimensional change after plating.
Shaft diameters and bearing seats receive additional attention when small surface changes can influence assembly.
Functional surfaces are identified early so plating does not unintentionally interfere with sealing, positioning or mechanical contact.
Where uncoated areas are required, masking requirements are coordinated with the finishing process and verified on finished parts.
Inspection datums are aligned with the functional assembly condition so final checks reflect how the part will actually be used.
Material selection affects machining efficiency, plating quality, corrosion protection and final dimensional stability. VMT machines carbon steel, mild steel, free-cutting steel and alloy steel parts, then coordinates zinc plating according to the drawing, final fit, coating requirement and application environment.
Carbon steel is widely used for zinc-plated shafts, pins, brackets, bushings, spacers and machine components. VMT reviews machining tolerances together with the required zinc coating so critical dimensions and assembly features remain within your drawing requirements after finishing.
Mild steel and iron are practical choices for brackets, mounting parts, structural components and general industrial hardware. CNC turning or milling establishes the required geometry first, while zinc plating is coordinated afterward to improve corrosion protection and appearance.
Free-cutting steels are suitable for efficient CNC turning of pins, sleeves, spacers, threaded components and other repetitive precision parts. Grades such as 12L14 or 1215 can be reviewed according to your drawing, machining requirements and zinc-plating specification before production.
Alloy steel is often selected when higher strength or wear resistance is required. Because heat treatment, hardness and strength level can affect the zinc-plating route and hydrogen-embrittlement risk, VMT reviews the complete material and finishing specification before confirming production.
A complete RFQ allows our engineers to evaluate not only machining cost, but also how zinc plating may affect dimensions, threads, fit, appearance and final inspection.
| RFQ Information | Why It Matters |
|---|---|
| 2D Drawing | Shows dimensions, tolerances, threads and finish notes. |
| 3D Model | Helps evaluate geometry and machining strategy. |
| Material Grade | Supports machining and finishing review. |
| Required Quantity | Determines prototype or production planning. |
| Zinc Plating Requirement | Defines the finishing scope. |
| Coating Thickness | May influence final dimensions. |
| Critical Dimensions | Helps establish the inspection plan. |
| Threads & Fits | Supports plating allowance or masking review. |
| Masking / No-Plate Areas | Protects functional surfaces. |
| Cosmetic Requirements | Defines visible-surface expectations. |
| Corrosion Requirement | Supports finishing and testing review. |
The machining route is selected before zinc plating according to part diameter, length, geometry, tolerance relationships, material and production volume. VMT combines turning, Swiss machining, milling, live tooling and secondary precision processes where required, while considering how the final zinc coating may affect threads, fits and critical dimensions.
CNC turning is suitable for shafts, pins, bushings, sleeves, threaded components and other rotational parts where diameter, concentricity and thread relationships are important.
For complex geometries requiring multiple features to maintain their relationships before finishing.
The required zinc finish should be defined by component function, corrosion exposure, appearance and drawing specifications. VMT coordinates finishing requirements together with the machining and inspection plan.
Reviewed when customers require a bright metallic appearance together with corrosion protection.
Specified according to project requirements because buildup can affect critical dimensions and assembly features.
Particular passivation or chromate conditions are confirmed before production when specified on the drawing.
Threads, precision fits, bearing seats, contacts and other functional areas can be reviewed for masking.
Visible areas and acceptable contact or fixture marks should be defined when appearance is important.
Salt-spray duration or other testing requirements are confirmed according to the customer specification and application.
VMT does not sell standard zinc-plated products. We manufacture custom components to your drawing, material, dimensional, finishing and inspection requirements.
Used for locating, motion and mechanical assemblies, these parts often combine close diameters, shoulders and threads. VMT controls machining datums and critical fits before plating, then verifies final dimensions to drawing requirements.
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Bushings and sleeves may contain precision internal and external diameters where coating buildup can influence final clearance or press-fit requirements.
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Male and female threaded parts require attention to plating exposure, gauge inspection and final assembly fit.
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Custom brackets may combine mounting holes, slots, locating surfaces and cosmetic areas that need coordinated machining and finishing control.
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Mounting blocks and support components often depend on hole location, flatness and mating surfaces that must remain functional after finishing.
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Custom industrial components can be machined according to your material, dimensional, corrosion and assembly requirements.
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Automotive and mobility components can be reviewed according to drawing requirements, functional fits and final coating specifications.
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For non-standard components, VMT evaluates geometry, material, tolerances, coating requirements and inspection needs directly from your drawing.
Request a QuoteInspection of the machined blank alone is not enough when critical dimensions may change during finishing. VMT checks parts at appropriate stages so final acceptance is based on the finished component requirements.
| Before Plating | Machined dimensions, threads, burrs, surface condition and critical features. |
| During Process | Key dimensions and process stability according to the inspection plan. |
| After Plating | Final dimensions, thread fit, appearance and functional surfaces. |
| When Required | Coating thickness, corrosion-related testing or customer-specified checks. |
| Before Shipment | Final inspection, documentation and protective packaging. |
For critical features, suitable inspection methods can include CMM measurement, gauges, thread gauges and other dedicated inspection tools depending on part geometry and drawing requirements.
A successful prototype is only useful if the same critical features can be reproduced during later production. VMT supports the transition by controlling machining references, inspection requirements and finishing specifications throughout the project.
Identify machining, plating and inspection risks before production.
Verify dimensions, assembly, threads and finish against your requirements.
Lock machining sequence, inspection points and finishing requirements after approval.
Maintain approved requirements across subsequent production batches and final packaging.
Zinc-plated steel CNC parts are used across equipment and OEM assemblies where corrosion protection, mechanical fit and repeatable mounting or motion features must be controlled together. VMT manufactures these parts from customer drawings rather than from a standard catalog.
Shafts, pins, sleeves, brackets, couplings and machine hardware for production equipment, fixtures and mechanical systems.
Brackets, shafts, spacers, threaded parts, bushings, pins and mounting components made to drawing and finishing requirements.
Standoffs, mounting hardware, threaded inserts, brackets and mechanical supports where corrosion protection and contact areas must be clearly defined.
Pins, shafts, brackets, spacers, bushings and connection parts requiring controlled fits, threads and locating features after finishing.
Brackets, anchors, mounting components, threaded hardware and structural fittings where zinc plating is specified for additional corrosion protection.
Shafts, brackets, fittings, mounting hardware and actuator components used in equipment assemblies where fit and corrosion exposure both matter.
Pins, shafts, spacers, link components, bushings and mounting parts for mechanical systems exposed to handling, wear and outdoor environments.
Mounting brackets, standoffs, threaded hardware and structural components where consistent assembly and protective finishing are required.
VMT has produced zinc-plated turned steel components in long tubular, stepped, cross-drilled, sleeve and pin-style structures. The manufacturing challenge is not only to turn the geometry, but to keep the functional relationships correct after secondary machining, deburring and plating.
The parts include long tubular components, stepped pins, sleeves and turned parts with cross-drilled holes. These structures are typical of zinc-plated hardware used in mechanical assemblies, industrial equipment, mounting systems and OEM mechanisms.
Long or relatively thin parts can be sensitive to vibration and deformation during turning. Cross holes must remain positioned from the turned datum, internal burrs must be removed before finishing, and zinc buildup can change OD, ID, thread or fit-related dimensions.
VMT establishes the primary turning datums first, machines secondary drilling or live-tool features from those references, deburrs the parts before finishing, and reviews which critical dimensions must be accepted after zinc plating rather than only before it.
Critical dimensions and fit-related features are checked before plating, then the finished parts are rechecked according to drawing requirements. Threads, bores, mating areas, appearance and masking requirements are included in the review when applicable.
The customer can manage turning, secondary machining, plating coordination, final inspection and protective packaging through one project workflow, reducing the risk of separate suppliers using different dimensional acceptance criteria.
Long shafts, sleeves and tubular parts are machined from controlled references before secondary features are added.
Side holes and cross features are referenced to the turned geometry to maintain their relationship with the part axis.
Critical OD, ID, thread and mating dimensions are checked with the final coating requirement considered before finishing.
Finished dimensions, functional fit and surface condition are checked after plating before protective packaging and shipment.
These comments were shared after customers received completed samples or production orders. They are not presented as feedback for one specific zinc-plated part; instead, they show what buyers value after working with VMT: finished-product quality, careful project support and secure delivery.
The customer thanked the VMT team after receiving the completed parts and specifically mentioned the etched-logo versions. This reflects confidence not only in machining, but in the completed product delivered after the full manufacturing process.
For finished machined parts, final inspection is only part of delivery quality. Organized protective packaging helps reduce scratches, part-to-part contact and mixing during international transport and makes incoming inspection easier for the customer.
The customer provided positive feedback after receiving three boxes from a production shipment and immediately discussed the remaining shipment. For OEM buyers, this kind of response indicates confidence in continuing the project rather than evaluating a one-off sample only.
A useful zinc-plating drawing must define what the finished part needs to do after coating—not only the nominal machined size before plating. This guide explains how coating thickness changes diameters, when a bore or thread may need masking, how to call out the final acceptance condition, and what information should be included in an RFQ.
Zinc plating adds material to every exposed surface. For a simple cylindrical shaft or bore, a useful first-pass engineering estimate is that the diameter changes by approximately twice the coating thickness because zinc builds on both sides of the diameter.
| Zinc Thickness per Surface | Approx. External Diameter Increase | Approx. Internal Diameter Reduction |
|---|---|---|
| 5 µm / 0.005 mm | +0.010 mm | −0.010 mm |
| 8 µm / 0.008 mm | +0.016 mm | −0.016 mm |
| 12 µm / 0.012 mm | +0.024 mm | −0.024 mm |
| 25 µm / 0.025 mm | +0.050 mm | −0.050 mm |
For any feature that controls assembly, the drawing should make clear whether the tolerance is required on the bare machined part or on the finished plated part. If the component must assemble after zinc plating, the functional acceptance dimension should normally be defined for the post-plating condition.
If the specified zinc build were approximately 8 µm per surface, the geometric diameter increase would be about 0.016 mm. Machining the bare shaft to Ø10.000 mm and then plating it would therefore risk pushing the finished shaft above the required size.
That does not mean the correct bare-machining target is automatically Ø9.984 mm. The actual pre-plating target must account for the specified minimum or controlled coating range, plating distribution, process capability and the drawing tolerance. VMT works backward from the required post-plating dimension during DFM instead of treating the pre-plating size as the final acceptance value.
A bore receives coating on its internal surface, so the usable diameter becomes smaller. For example, a nominal 8 µm build on each side gives an approximate 0.016 mm reduction in bore diameter. That may be insignificant for a loose clearance hole but critical for a bearing seat, locating bore, precision sleeve, pin fit or press fit.
For fit-critical bores, the drawing should identify one of two strategies: final size after plating, allowing the manufacturing team to establish a suitable pre-plating target; or mask / no plate when the fit cannot tolerate coating buildup. The choice depends on the permitted fit range, coating requirement and geometry.
Threads should not be treated as a simple smooth diameter because coating on the flanks changes the effective thread geometry and can tighten the fit. The drawing should define the required final thread designation and whether acceptance is required after plating.
For critical functional threads, VMT reviews whether the feature should receive controlled allowance, masking or another agreed process route, then checks the finished thread with the appropriate inspection method. Where GO / NO-GO gauges are specified, acceptance should reflect the finished plated condition rather than only the bare machined thread.
This is especially important for internal threads, fine pitches and assemblies where both mating components have protective finishes.
Not every critical feature should be controlled by machining undersize or oversize before plating. Masking is often the safer route when the available dimensional tolerance is comparable to the coating buildup or when a functional surface must retain direct base-metal contact.
Typical no-plate or masking candidates include bearing seats, precision dowel holes, electrical contact or grounding surfaces, sealing faces, tight press fits and precision locating datums. These areas should be marked directly on the drawing rather than left for the plater to decide.
For electrodeposited zinc on iron and steel, ASTM B633 defines four standard minimum thickness classes. The correct class is selected according to the specified service condition and customer requirement; thicker is not automatically better for a precision component because dimensional buildup also increases.
| ASTM B633 Classification | Minimum Zinc Thickness | Service Condition |
|---|---|---|
| Fe/Zn 5 | 5 µm | SC 1 — Mild |
| Fe/Zn 8 | 8 µm | SC 2 — Moderate |
| Fe/Zn 12 | 12 µm | SC 3 — Severe |
| Fe/Zn 25 | 25 µm | SC 4 — Very severe |
A thicker coating can provide a higher corrosion-protection requirement when the specification calls for it, but it also increases external diameters, reduces internal diameters and can affect threads and tight fits. The finish type, passivation, appearance and corrosion-test requirement must therefore be reviewed together with the dimensional tolerance.
High-strength steel requires additional review because electroplating processes can introduce hydrogen-embrittlement risk. Do not submit only “alloy steel” on the RFQ. Provide the exact grade, heat-treatment condition, hardness or tensile-strength requirement and the plating specification so the pretreatment and post-treatment requirements can be evaluated before production.
ASTM B633 also contains specific hydrogen-embrittlement provisions and states that very high-strength steels above the standard's stated limit should not simply be zinc electroplated under the ordinary specification. VMT therefore confirms the material condition before accepting the finishing route.
A clear RFQ reduces the risk that the CNC supplier, plating supplier and customer use different definitions of an acceptable finished part.
| Drawing / RFQ Requirement | What Should Be Defined |
|---|---|
| Base Material | Exact steel or iron grade. |
| Heat Treatment | Condition, hardness or strength requirement when applicable. |
| Zinc Specification | ASTM B633 or the customer / industry specification required by the project. |
| Coating Thickness | Required class or thickness range where specified. |
| Passivation / Appearance | Clear, blue or other specified finish condition. |
| Critical Dimensions | Identify which dimensions must be accepted after plating. |
| Threads | Final thread designation and inspection condition. |
| No-Plate Areas | Mark masking boundaries directly on the drawing. |
| Cosmetic Surfaces | Identify visible or appearance-critical surfaces. |
| Corrosion Test | Specify the test only when required by the drawing or purchasing specification. |
| Inspection | CMM, dimensional gauges, thread gauges, coating thickness or other required records. |
Send VMT your drawing, exact material grade, batch or annual quantity, zinc-plating specification and the dimensions that must be accepted after plating. If the drawing does not yet define coating allowance, masking or finished-condition tolerances, our engineers can review these items during DFM before quotation.
Send VMT your drawing, material, quantity, critical tolerances and zinc-plating requirements. Our engineers will review machining feasibility, plating-related dimensional risks, functional surfaces and inspection requirements before quotation.
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