Introduction: Why Material Choice Defines Everything in CNC Machining
When buyers search for a machined components manufacturer in India, the conversation almost always starts with geometry — what the part looks like and what dimensions it needs. But experienced procurement teams and design engineers know that material choice is equally important. The material determines which machines are needed, which cutting tools are required, what surface finishes are achievable, how the part behaves in service, and ultimately what the part costs.
Nathan Engineering has built deliberate machining capability across a wide range of materials — not just mild steel and aluminium, but stainless steel, brass, engineering plastics, and specialist alloys. This guide walks through each material category and explains what Nathan Engineering can produce, what tolerances are achievable, and what industries typically require each.
Mild Steel and Alloy Steel Machined Components
Grades Nathan Engineering machines
EN8 (C45) for general structural machined components. EN24 (4340) for high-strength applications requiring heat treatment. EN36 for case-hardened components with hard surface and tough core. AISI 4140 for shafts, gears, and high-stress structural parts. Mild steel (IS2062, ASTM A36) for general fabricated and machined assemblies.
Typical components
- Shafts and spindles — turned from EN8 or EN24 bar, key-seated, threaded, and ground where required
- Gear blanks — turned to outside diameter and face, then passed for gear cutting
- Bearing housings — VMC-milled with precision-bored bearing seats and tapped mounting holes
- Hydraulic valve bodies — complex multi-port manifold machining in alloy steel
- Jig and fixture bodies — precision-machined tooling components for production line use
Tolerances and surface finish
Standard: ±0.05 mm, Ra 3.2 µm. Precision: ±0.02 mm, Ra 1.6 µm. High-precision bearing fits: ±0.008 mm on bore diameter with Ra 0.8 µm, achieved by fine boring followed by honing.
Stainless Steel Machined Components
Why stainless steel machining is a specialist skill
Stainless steel work-hardens rapidly when rubbed rather than cut cleanly. This means that incorrect cutting speeds, dull tools, or insufficient coolant cause the material to harden ahead of the cutting edge — resulting in accelerated tool wear, poor surface finish, and parts that require rework or scrapping. Many general-purpose machine shops avoid stainless steel for this reason.
Nathan Engineering has invested in grade-specific tooling, cutting parameter libraries, and operator training specifically for stainless steel machining. As a result, the company consistently produces stainless machined components that meet dimensional tolerances and surface roughness specifications without rework.
Grades machined
SS303 (free-machining grade for turned components), SS304 (general purpose austenitic), SS316/316L (marine and pharmaceutical), SS416 (martensitic, heat-treatable), SS630/17-4PH (precipitation-hardened, high-strength aerospace grade).
Typical components
- Pump shafts — SS316 turned shafts for fluid handling applications
- Valve bodies — SS304 and SS316 bodies for food and pharmaceutical process equipment
- Flanges and fittings — pressure-rated SS316L flanges with precision-faced sealing surfaces
- Surgical instrument components — SS303 and SS316 turned and milled components with Ra 0.4 µm finish
- Marine fasteners — SS316 turned bolts, nuts, and studs for offshore and marine applications
Aluminium Machined Components
Why aluminium machining is Nathan Engineering’s highest-volume capability
Aluminium’s excellent machinability — high cutting speeds, low cutting forces, clean chip formation — makes it the most efficient metal to machine. Combined with its low density (one-third the weight of steel), excellent corrosion resistance in anodised form, and good thermal and electrical conductivity, aluminium is the preferred material for aerospace, electronics, automotive, and precision instrument applications.
Grades machined
6061-T6 (the workhorse structural grade — excellent machinability, good strength, weldable). 7075-T6 (high-strength aerospace grade, excellent machinability but not weldable). 5052 (good corrosion resistance, moderate strength, used in marine and architectural applications). 2024-T3 (high fatigue strength, aerospace structural use). Cast aluminium grades ADC12, A380 (post-machining of die castings).
Typical components
- Electronic enclosures — 6061-T6 machined and anodised housings for PCB and power electronics
- Aerospace structural brackets — 7075-T6 machined brackets with precision-bored attachment holes
- Heat sinks — 6061-T6 machined heatsinks with fin arrays for power electronics cooling
- Camera and optical housings — 6061-T6 precision-machined bodies for imaging systems
- Hydraulic manifold blocks — 6061-T6 multi-port manifolds for fluid power systems
- Die casting post-machining — bearing seats, sealing faces, and thread features in ADC12 castings
Tolerances and surface finish
Standard: ±0.05 mm, Ra 3.2 µm. Precision: ±0.01 mm, Ra 0.8 µm. High-precision optical/aerospace: ±0.005 mm on specific features with Ra 0.4 µm, achievable with diamond tooling on 6061-T6 and 7075.
Brass and Copper Machined Components
The benchmark machinability material
Brass (C360 free-machining brass) is considered the reference material for machinability — all other materials are rated against it. It produces clean, short chips, gives excellent surface finish at high cutting speeds, and requires no coolant for most operations. The result is fast cycle times and extremely consistent dimensional quality.
Typical components
- Electrical connectors and terminals — turned brass pins, sockets, and contacts
- Plumbing fittings — threaded adapters, compression fittings, and valve bodies
- Instrument components — turned brass housings for pressure gauges and flow meters
- Decorative components — machined brass knobs, inserts, and architectural fixings
- Electrical bushings and standoffs — precision turned brass spacers for PCB assemblies
Copper machining
Copper (C110 electrolytic tough pitch) is softer and more difficult to machine cleanly than brass but necessary for applications requiring maximum electrical conductivity. Nathan Engineering machines copper bus bars, contact pads, and electrical connector bodies for switchgear and power distribution applications.
Engineering Plastics Machined Components
When plastic machining is the right choice
Not all plastic components need to be injection moulded. For prototype quantities, low-volume production (under 500 pieces), or components requiring tolerances tighter than injection moulding can achieve, CNC machining from plastic stock is the correct manufacturing route.
Materials machined
- POM / Acetal (Delrin) — excellent dimensional stability, low friction, ideal for gears, slides, and bearing surfaces
- Nylon PA6 and PA66 — good strength and wear resistance, used for bushings, guides, and structural components
- PTFE — chemical resistance, low friction, essential for seals, liners, and chemical process components
- PEEK — high-temperature performance (continuous service to 250°C), used for aerospace and medical components
- UHMWPE — exceptional wear resistance, used for wear pads, guide rails, and impact absorbers
- Polycarbonate (PC) — optical clarity with good impact resistance, used for lens covers and inspection windows
Plastic machining considerations
Plastics absorb moisture and expand — dimensional stability requires pre-conditioned blanks and temperature-controlled inspection. Plastics generate heat during machining — sharp tooling and correct cutting speeds prevent melting and poor surface finish. Nathan Engineering’s plastic machining processes address both of these challenges.
Quality Control Across All Materials
Nathan Engineering’s quality system applies consistently regardless of material:
- All incoming material verified against certification before production begins
- First Article Inspection on every new part number
- In-process dimension checks at defined intervals
- Final inspection against drawing with documented results
- CMM measurement for geometric tolerances and critical dimensions
- Surface roughness measurement for functional surfaces
Contact Nathan Engineering
- Email: nathan@nathanengineering.co.in
- Phone: +91 93601 75927
- Website: www.nathanengineering.in
Submit your drawings with material and tolerance requirements for a quotation within 24–48 hours.
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.
