Berkshires Precision CNC Machining Service

Every job starts with the print and the model. We check datums, callouts and the surfaces that actually matter for function. Then we pick the machine. That choice matters more than most people think. A part that looks simple on paper can need 5-axis work because of a single angled hole or a face that cannot be reached in one orientation.

The quote and DFM analysis come back within 12 hours. That review flags thin walls, deep pockets, sharp internal corners and features that sit below the tool radius. Production can start within 24 hours of approval. Parts normally ship in 3–5 days, and the historical late-delivery probability stays below 2%.

We hold ±0.005 mm (±0.0002 in) where the drawing demands it, but we do not apply it to every surface by default. Tightening a non-critical face adds cost and inspection time without helping the part work. Tell us which dimensions are functional and which are reference, and the process gets cleaner.

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  Print reviewDatums, tolerances and functional surfaces are identified before programming.
• 2
  Machine selection3-axis, 4-axis, 5-axis or mill-turn, based on reach and setup count.
• 3
  DFM feedbackWithin 12 hours, with the features that will drive cost called out.

Three-axis machining moves the tool in X, Y and Z. It is the fastest and cheapest option for prismatic parts, plates, brackets and housings that can be reached from a few faces. We run 27 three-axis machines for that work. If a part needs four sides, a 4-axis mill with a rotary table cuts the setup count.

Five-axis work adds rotation around two axes, usually A and B. The tool approaches the part from almost any angle without re-fixturing. That matters for impellers, medical housings, angled ports and parts with compound surfaces. We run 16 simultaneous 5-axis machining centers, plus a Ø400 mm rotary table for round work.

For parts that are turned and milled, 16 mill-turn centers cut both operations in one setup. Maximum processing size reaches 4,000 mm. Travel envelopes cover 4,000 × 400 × 150 mm for long parts, 750 × 1,150 × 550 mm and 600 × 600 × 600 mm for mid-size work, and 500 × 500 × 450 mm or 500 × 310 × 200 mm for compact parts. In total we run 127 high-precision CNC machines across three wholly-owned plants.

Aluminum is the default for prototypes and light production. We machine 6061, 6061-T6, 2024, 5052, 5083, 6063, 6082, 7075 and ADC12. 7075 gives high strength but moves more after roughing, so we leave stock and take a finishing pass. 6061-T6 is the stable choice for tight tolerances on thin walls.

Stainless grades run from 303 and 304 to 316L, 17-4PH and 440C. 303 machines cleanly and suits bushings and fittings. 316L is the pick for medical and marine parts. 17-4PH holds strength after heat treatment and is common in aerospace and medical work. Tool wear is higher, so feeds and speeds are set conservatively.

Steel covers 1018, 1045, 4130, 4140, 4340, A36 and tool steels. 4140 and 4340 are used for stressed parts; 4130 for welded frames. Titanium TA1, TA2 and TC4 (Ti-6Al-4V), Inconel and magnesium AZ31B / AZ91D sit in the harder group. Inconel and titanium cut slowly and generate heat, so cycle times rise and we plan for more tool changes.

Copper and brass include C101, C103, C110, beryllium copper, C27400, C28000 and C36000. Plastics cover ABS, PC, PMMA, POM, PA, PEEK, PP, HDPE and carbon fibre. POM and PEEK hold tight tolerances well; unfilled plastics are easier to hold than carbon-filled grades.

As-machined surfaces sit at Ra 1.6–3.2 μm. Where a sealing face or bearing bore needs better, we hold Ra 0.8–1.6 μm, and fine finishing reaches Ra 0.2–0.8 μm. Surface callouts should match the function. Polishing a cosmetic face is fine; polishing a locating face can change the fit.

Inspection is 100% before shipment. That includes a raw material check, in-process monitoring and a final inspection. Reports are available on request, including CMM data where the drawing calls for it. We work to ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. The qualification rate across shipped parts is 99.99%.

Finishing options include anodizing (clear, colour, hardcoat, conductive), electroless nickel, zinc, silver and gold plating, powder coating and black oxide, plus bead blasting, tumbling, brushing and polishing. Laser marking and engraving are available down to a minimum character height of 1.5 mm. Heat treatment, precision grinding and assembly can be included so the part arrives ready to fit.

• 1
  As machinedRa 1.6–3.2 μm, suitable for most structural faces.
• 2
  High finishRa 0.8–1.6 μm for sealing and bearing surfaces.
• 3
  Fine finishRa 0.2–0.8 μm when the print calls for it.

Machining fits parts with tight tolerances, complex geometry or a need for real material properties. It also fits low to medium volumes where tooling cost would not pay back. There is no minimum order quantity, so a single prototype and a 10,000+ part run both go through the same process.

For a part with no tight tolerances that will be made in high volume, die casting or vacuum casting is usually the better route. For a hollow shell with thin walls, sheet metal or 3D printing can be faster. Machining still wins when the part must hold ±0.005 mm or when the material has to be the final alloy.

If a design is still moving, send the model and note which dimensions are fixed. We can quote both the prototype and a production path so the two are not disconnected. Uploads are secure and confidential, and an NDA is available on request.