CNC Machining Services

CNC machining, short for computer numerical control machining, is a subtractive manufacturing process that removes material from solid metal or plastic stock to produce a finished part. A CAD model is converted into a tool path, and the CNC machine drives cutting tools across the workpiece on multiple axes to cut the geometry to your drawing. Because the same program runs every cycle, machined parts are highly repeatable, which makes the process well suited to both prototypes and recurring production parts.

Standard production lead time is 4 to 8 weeks, with first-article timing confirmed at the quote stage. Rush programs can be reviewed case by case.

Standard machined tolerance is ±0.005 inch, and we hold down to ±0.0005 inch on critical features verified by CMM. Our engineering team confirms achievable tolerances against your drawing at the feasibility review.

We machine aluminum, carbon and alloy steel, stainless steel, titanium, brass, and copper, along with engineering thermoplastics such as POM (Delrin), PTFE, polycarbonate, and nylon. Material choice drives machinability, corrosion resistance, and mechanical properties, so if your part calls for a specific alloy or temper our engineering team confirms the best fit at the feasibility review.

Parts ship as-machined or with secondary finishing including anodizing, powder coating, plating, passivation, heat treatment, and bead blasting. As-machined surfaces reach down to Ra 0.4 micrometres on critical features, and the right finish depends on your appearance, corrosion resistance, and chemical resistance requirements.

The biggest cost levers are part geometry, material selection, tolerances, and volume. Simplifying internal corners, relaxing tolerances where the design allows, choosing a more machinable alloy, and committing to recurring volume all bring the per-part price down. Our engineering team flags these opportunities during the manufacturability review so the quote reflects the most cost-effective approach.

In turning, the workpiece rotates while the cutting tool is fixed - this is used for cylindrical and conical geometry such as shafts, bushings, and threaded components. In milling, the cutting tool rotates while the workpiece is held stationary - this produces flat surfaces, pockets, contours, and complex features. Multi-axis machines combine both approaches in a single setup to reduce handling and improve accuracy.

Because machining is a subtractive process, it removes material without altering the base metallurgy, so a machined part retains the tensile strength, yield strength, and ductility of the stock it is cut from. The bigger drivers of in-service performance are material and temper selection and the part geometry: sharp internal corners and abrupt section changes concentrate stress and lower fatigue strength, while generous fillets improve toughness and impact strength. For parts that see cyclic loading or wear, our engineering team reviews the drawing and recommends an alloy and heat treatment that meet the required strength, fatigue, and wear resistance.

There is no fixed unit minimum. Overseas machining often delivers its largest percentage savings at lower and prototype volumes, so you do not need high volume to benefit. The fit is about overall program value and ongoing potential rather than a single large run; we will tell you at the quote stage whether your part is a good fit and recommend the most cost-effective approach.

All production runs to ISO 9001 and IATF 16949 with in-process and CMM inspection. Every shipment includes a Certificate of Conformance and a dimensional inspection report, and third-party inspection is available on request.

You have one U.S. point of contact who manages quoting, programming, production scheduling, quality documentation, and logistics. There is no offshore quote desk between you and the production line.

CNC machining cost depends on material, part complexity, tolerance requirements, and order volume. The most common hidden cost driver we see: over-specified internal geometry. Tight radii, specific fillet sizes, or edge-break callouts added for aesthetics rather than function force specialty tooling, multiple setups, and slower feed rates on small-diameter end mills, all of which increase price without improving the part. CNC turning tends to cost less than multi-axis milling. Contact our team for a quote based on your requirements.

Redstone translates every print callout into a ballooned inspection template, so nothing is left unchecked. Critical tolerances are identified based on end use: which dimensions drive assembly fit, which features control downstream dimensions. Those driving dimensions get extra rigor and are reviewed with the manufacturer before production begins. Inspection methods include CMM, height gauges, thread gauges, and optical measurement. Consistent conforming lots earn reduced inspection frequency over time, while targeted checks remain for anticipated failure modes.

Redstone finds issues before parts ship. When a part fails inspection, Redstone runs a 100% sort on the affected lot, quarantines nonconforming inventory, stops production, and performs root cause analysis before any corrective action. Disposition is rework, replacement, or credit. Redstone guarantees the parts: repair, replace, or refund, with air-freighted replacements when rework is not feasible.

The most common design mistake is specifying tolerances tighter than the machining process can reliably hold. Tight internal shapes that require specialty tooling or multiple setups inflate cost quickly. Cutting tools can break edges or add radii that achieve the function, so adding callouts where none are needed only drives price. On finished parts, coating thickness is often overlooked. Plating or anodize adds material that changes bore diameter on precision holes, so those dimensions should account for coating build-up at design.

3D printing is an additive process that builds parts layer by layer, while CNC machining is a subtractive process that removes material from solid stock. CNC machining produces parts with higher tensile strength, tighter tolerances, and better surface finishes. 3D printing is ideal for rapid prototype validation, while CNC machining handles production-grade metal and plastic components.