High-Precision Brass CNC Machined Parts Supplier
Overview
XCM CNC provides high-precision brass CNC machining focused on dimensional control of micro holes, fine threads, fit faces, and conductive contact areas, supported by ISO 9001 and IATF 16949 quality systems plus equipment such as Matsuura and DMG precision machining centers.
For RF connectors, terminals, sensor fittings, and small instrument parts, H7 and H8, the workable range for +/-0.003 mm features, surface finish targets, and pre- and post-plating reinspection are confirmed first, then precision machining and inspection are released. MOQ can begin from 1 piece, with sample lead time often reviewed in the 3-7 day range.
Key Capabilities
Machining Parameters and Tolerances
- Materials: C360 (free-cutting brass), C260 (cartridge brass), C510 (phosphor bronze), selected by conductivity, wear resistance, and lead-free requirement
- Tolerance: +/-0.003 mm (+/-0.00012 inch), IT5 or IT6 accuracy, +/-0.01 mm shaft/bore fits; h6/H7 available
- Surface Finish: Ra 0.8 um turned surfaces, Ra 1.6 um milled contact faces, Ra 0.4 um ground surfaces, Ra 0.2 um polished surfaces
- GD&T: Coaxiality 0.012 mm, runout 0.01 mm, cylindricity 0.011 mm, roundness 0.006 mm, position 0.015 mm
- Max Size: 3-axis milling 3000 x 1600 x 1400 mm; turning diameter 1250 x length 2000 mm
- Surface Treatment: Nickel plating (3-20 um), anti-tarnish finish, passivation, polishing by order review
- Thread: Internal from M1.4, external from M2.0, up to M220; NPT / BSP / G / PT pipe threads; depth up to 4xD
- Precision Limit: +/-0.003 mm dimensional tolerance, roundness 0.006 mm, position 0.015 mm (specific features, by drawing review)
Precision Tolerance Limits for Micro Holes and Fine Features
Selected brass precision features under 100 mm can be controlled to +/-0.003 mm. Minimum drilled hole size can start from 0.2 mm and minimum milled hole size from 0.3 mm. Locating and fit bores can follow H7 around +/-0.006 mm or H8, while shaft diameters can follow h6 or h7 around +/-0.005 mm. Hole depth ratios up to L/D 10 can be reviewed, with blind-hole bottom stock around 0.3 mm when the structure allows it.
GD&T Control for Connector and Fitting Geometry
Brass connectors and terminals can follow full GD&T callouts such as roundness 0.006 mm, cylindricity 0.011 mm, coaxiality 0.012 mm, circular runout 0.01 mm, total runout 0.012 mm, and position 0.015 mm for hole groups or locating bores. Inspection can use Hexagon CMM and roundness equipment, with datum choice and inspection path confirmed before machining.
Surface Roughness Grading for Conductive and Sealing Faces
Brass roughness can be graded by function, such as turned outer diameters at Ra 0.8 um, precision milled contact faces at Ra 1.6 um, ground sealing faces at Ra 0.4 um, and polished conductive faces at Ra 0.2 um. Conductive faces and sealing edges should be marked separately instead of pushing the whole part to one finish level. A roughness tester can be used to confirm key faces item by item to the drawing requirement.
Pre- and Post-Plating Dimensional Verification with CMM
Nickel plating in the 3-20 um range changes thread, fit-bore, and contact-face dimensions on small brass parts, so machining allowance can be reserved before plating and CMM reinspection can confirm the critical features afterward. Inspection can use equipment such as a Hexagon CMM and a WanHao VMS vision system, while threads can be checked by go and no-go gauges. FAI and plating-thickness reports can be added by order.
Specifications
| Product Name | High-Precision Brass CNC Machined Parts |
|---|---|
| Manufacturer | XCM CNC |
| Factory Location | Shenzhen, Guangdong, China |
| Quality System | ISO 9001, ISO 13485, IATF 16949, GJB9001C |
| Machining Process | Precision CNC turning, CNC milling, drilling, tapping, deburring |
| Material | Brass |
| Material Grade | C360, C260, C510 selected by conductivity, wear, and lead-free requirement |
| Tolerance | +/-0.03 mm standard CNC tolerance, critical dimensions by drawing review |
| Precision Tolerance | +/-0.003 mm for selected small precision features after review |
| Surface Roughness | Ra 1.6 um contact surfaces, fine machined surfaces by requirement |
| Surface Treatment | Plating or anti-tarnish finish after precision machining by order review |
| Inspection | Thread gauge, CMM, roughness tester, and dimensional inspection by order requirement |
| Application | RF fittings, terminals, sensor connectors, and small precision instrument parts |
| Key Features | Micro holes, fine threads, fit surfaces, conductive contact faces, and plating size effect |
| Critical QC Requirements | Burr control, thread inspection, roughness verification, and post-plating recheck |
| Batch Range | Prototype to repeat precision batches by drawing review |
| MOQ | 1 Piece |
| Typical Lead Time | 10-15 business days after drawing review |
| Drawing Formats | STEP, IGS, DWG, PDF, X_T |
Applications
High-Precision RF Connector Housings and Antenna Bases
Typical Parts: RF connector housing, antenna base, coaxial terminal seat
Critical dimensions on brass RF connector housings can be controlled to +/-0.003 mm, with coaxiality around 0.012 mm and fine threads checked item by item with go and no-go gauges. CNC machining focuses on bore size, thread coaxiality, and burr control, then rechecks the fit faces again after nickel plating in the 3-20 um range.
Micro Conductive Terminals, Pins, and Terminal Seats
Typical Parts: Micro terminal, contact pin, terminal seat
Micro conductive terminals can start from drilled hole sizes around 0.2 mm, while pin roundness can be controlled around 0.006 mm and turned surfaces around Ra 0.8 um. One-setup machining of outer diameters, end faces, and hole locations helps reduce accumulated error from repeated positioning.
Precision Valve, Pneumatic, and Sensor Fittings
Typical Parts: Precision fitting, valve seat, sensor connector seat
Fit bores on precision fittings can follow H7 or H8 classes, sealing faces can be machined around Ra 0.8 um, and pipe thread standards such as NPT, BSP, G, and PT can be supported. The route should confirm bore tolerance and datum first, then release deburring, thread inspection, and post-plating reinspection.
Small Precision Parts for Instruments and Watches
Typical Parts: Instrument knob, micro gear, adjustment sleeve
Small instrument parts can be reviewed for hole position around 0.015 mm, minimum slot width around 0.3 mm, and cylindricity around 0.011 mm on outer diameters. CNC finishing should define inspection around hole locations, small slots, and contact faces, with roughness graded by function.
Why Choose Us
Certified Systems and Equipment Coverage
The factory organizes quality flow under ISO 9001, ISO 13485, IATF 16949, and GJB9001C, while using DMG, Mazak, Matsuura, Brother, and other equipment for brass turning, milling, and multi-face machining. For brass fittings, terminals, and small precision parts, drawing review can confirm conductive faces, threads, and surface-treatment requirements together.
Broad Size Coverage
The machining range covers both small connector-scale parts and larger structural blocks. Three-axis travel can reach 3000 x 1600 x 1400 mm and turning diameter can reach 1250 mm, while the actual route still depends on fixturing, grade, and surface-treatment requirements.
Tiered Equipment Strategy for Cost and Quality
XCM CNC uses a tiered equipment mix from mainland China, Taiwan, Japan, and Europe or the US. Lower-tolerance work can be arranged on domestic or Taiwan machines, while tighter precision work can move to imported machines such as DMG or Mazak. That matching helps control cost without putting simple features onto high-hour-rate equipment.
Datums and Reinspection Paths Confirmed First
H7 and H8 bores, fine threads, and fit-critical outer diameters are reviewed together with datum choice and reinspection method before machining starts. Hexagon CMM, roundness testing, and roughness inspection can all be selected according to the feature so the measurement route is already defined when the first article is made.
Two-Stage Dimensional Validation Before and After Plating
Conductive faces and fit dimensions on brass parts can be checked twice, once before plating to reserve allowance and once after plating to confirm the real size effect of the 3-20 um thickness range. Critical dimensions are defined by the drawing and written into the order requirements instead of left to verbal agreement.
FAQ
How do you choose C360, C260, or C510 for a brass CNC part?
Selection usually starts from conductivity, wear, self-lubrication, forming demand, and whether a lead-free requirement applies. Final grade choice still depends on the drawing, contact faces, post-treatment, and the real use condition, so one material name should not be substituted automatically for another.
What is the tightest tolerance you can hold on small brass features?
On selected small precision features below 100 mm, tolerance can reach +/-0.003 mm, locating bores can follow H7 around +/-0.006 mm, and roundness can be controlled around 0.006 mm. Whether those limits apply to every feature still depends on hole size, depth, part structure, and the inspection method.
What GD&T controls can you apply to brass connector housings?
Brass connector housings can follow GD&T values such as coaxiality 0.012 mm, circular runout 0.01 mm, position 0.015 mm, and perpendicularity 0.02 mm. Inspection can be performed on a Hexagon CMM, with datum selection and inspection path confirmed before machining, and the report format can follow the customer template.
How do you specify surface roughness for brass conductive and sealing faces?
Roughness is graded by function, such as Ra 0.8 um on turned outer diameters, Ra 1.6 um on precision milled contact faces, Ra 0.4 um on ground sealing faces, and Ra 0.2 um on polished conductive faces. Conductive and sealing features are marked separately rather than pushing the whole part to one finish level.
Can you hold H7 and H8 holes or fine threads on precision brass parts?
Yes. H7 and H8 bores and fine threads can be reviewed according to the drawing, with common fit-bore values around H7, H8, or +/-0.006 mm. Whether the same route works for every feature still depends on hole diameter, depth, thread class, and the planned inspection method.
How do you account for plating thickness when machining precision brass parts?
Nickel plating in the 3-20 um range changes the size of fit faces and threads, so machining allowance is reserved first and the key features are rechecked with CMM after plating. Threads can then be verified with go and no-go gauges, while masking on conductive faces is confirmed by order.
Request a CNC Machining Quote from XCM CNC
Send us your drawings. Our team will review the file and reply with a machining quote. MOQ: 1 piece, with competitive low-cost pricing.
Email: [email protected] | WhatsApp: +8618638951317
