OEM CNC machined steel parts per specific drawings in China
We are a China-based CNC machining workshop focused on OEM CNC machined steel parts per specific drawings in China. Customers send us engineering drawings, CAD files or physical samples, and we machine carbon steel and alloy steel components exactly to the dimensions, tolerances, threads and surface requirements defined on the print.
Our daily work covers carbon steel CNC machining in China, CNC machining alloy steel per drawing, custom machined steel hardware and every kind of OEM machined steel component. Orders run from a single steel part prototype machining piece, through small pilot batches, all the way to repeat large-volume production with stable batch-to-batch consistency.
Related machined steel products
A quick view of the steel parts we machine for overseas customers: brackets, shaft bushings, threaded nuts, bevel gears, hydraulic valve blocks and alloy gear shafts.
Steel CNC machining capability at a glance
We can machine all kinds of steel, carbon steel and alloy steel parts according to customer drawings or physical samples. The eight points below summarize how an order moves from a print or a sample to a finished, packed steel component.
Production per specific drawings
Every OEM machined steel component follows the customer's own drawing. We read STEP, IGES, X_T, DWG, DXF and PDF files, respect all marked tolerances, threads, chamfers and surface notes, and never change a dimension without written confirmation.
Production per samples
When no drawing exists, customers send a physical sample. We measure it, redraw the part, match the steel grade and reproduce it. This reverse-engineering route is widely used for replacement custom machined steel hardware and obsolete spare parts.
Carbon steel CNC machining in China
Routine carbon steel grades include CNC machined 1018, CNC machined 1020, 1035, 1045 and 1050 parts, plus Q235 and A36 structural steel. Low and medium carbon steels are turned, milled, drilled, tapped and welded every day.
CNC machining alloy steel per drawing
Alloy work covers CNC machined 4140, CNC machined 5140, 4130, 4340, 42CrMo, 35CrMo, 40Cr, 20CrMnTi and bearing steel GCr15. Raw material can be ordered in hot-rolled, cold-drawn, forged or pre-hardened condition as the print requires.
Steel part prototype machining
Single-piece and first-article orders are welcome. Steel part prototype machining allows design engineers to check fit, assembly, thread engagement and loading behavior before committing to a production batch.
Small to large batch production
The same line handles 1-off custom CNC machined steel parts, runs of several hundred and repeated orders of tens of thousands. Fixtures, tooling lists and inspection records are kept so repeat orders match the first batch.
Combined machining processes
CNC turning, CNC milling, drilling, boring, tapping, reaming, surface and cylindrical grinding, gear hobbing, broaching, slotting and wire cutting can be combined on one part under one roof.
Custom hardware for many industries
Our custom machined steel hardware goes into hydraulic systems, gearboxes, agricultural machinery, construction equipment, material handling lines, pumps and valves, packaging machines and transmission assemblies.
Steel grades under different standards and their typical machined parts
Drawings arrive with SAE/AISI, EN/DIN, JIS or Chinese GB grade designations. The table below lists the grades we machine most often and their near-equivalent designations across standards. Equivalents are approximate references; the final material always follows the grade stated on the customer drawing or specification.
| SAE / AISI | Chinese GB | EN / DIN | JIS | Steel family |
|---|---|---|---|---|
| 1018 | 20 (near) | C15E / C22, 1.0402 (near) | S15C / S20C | Low carbon steel |
| 1020 | 20 | C22, 1.0402 | S20C | Low carbon steel |
| 1035 | 35 | C35, 1.0501 | S35C | Medium carbon steel |
| 1045 | 45 | C45, 1.0503 | S45C | Medium carbon steel |
| 1050 | 50 | C50, 1.0540 | S50C | Medium carbon steel |
| A36 / Q235 | Q235 | S235JR, 1.0038 | SS400 | Structural mild steel |
| 4130 | 30CrMo | 25CrMo4, 1.7218 | SCM430 | Cr-Mo alloy steel |
| 4140 | 42CrMo | 42CrMo4, 1.7225 | SCM440 | Cr-Mo alloy steel |
| 4340 | 40CrNiMo | 36CrNiMo4, 1.6511 | SNCM439 | Ni-Cr-Mo alloy steel |
| 5140 | 40Cr | 41Cr4, 1.7035 | SCr440 | Chromium alloy steel |
| 35CrMo class | 35CrMo | 34CrMo4, 1.7220 | SCM435 (near) | Cr-Mo alloy steel |
| 52100 | GCr15 | 100Cr6, 1.3505 | SUJ2 | Bearing steel |
CNC machined 1018
1018 is a carburizing low-carbon steel with good weldability and mild cutting forces. CNC machined 1018 parts include dowel pins, rods, spacers, shafts, mounting studs and lightly loaded custom machined steel hardware that later receives case hardening.
CNC machined 1020
1020 mild steel machines and welds cleanly and is inexpensive. Typical CNC machined 1020 work covers brackets, base plates, welded frames, fixtures, covers, adapters and structural OEM machined steel component families where toughness matters more than hardness.
CNC machined 1045
1045 is a versatile medium-carbon steel that can be induction hardened. CNC machined 1045 parts include hydraulic valve blocks, gear blanks, rollers, splined shafts, spindles and the nickel-plated 1045 hydraulic valve blocks shown in this page.
CNC machined 4130
4130 chromium-molybdenum steel offers high toughness with low weight. CNC machining alloy steel per drawing in 4130 commonly produces frame fittings, tube adapters, brackets, couplings, clamps and load-bearing custom CNC machined steel parts for machinery.
CNC machined 4140
4140 is a through-hardening Cr-Mo alloy with excellent strength and wear resistance. CNC machined 4140 gear shafts, axles, spindles, high-load bushings, pinion shafts and die components are among the most repeated alloy orders on our floor.
CNC machined 5140 / 40Cr
SAE 5140 corresponds closely to Chinese 40Cr. CNC machined 5140 parts include gears, shafts, sleeves, pins, bushings and automotive-style transmission components, often quenched and tempered before finish machining.
CNC machined 4340
4340 nickel-chromium-molybdenum steel delivers very high toughness and fatigue strength. We machine 4340 into heavy-duty shafts, transmission gears, drive components, torsion parts and critical custom machined steel hardware under dynamic loads.
CNC machined 42CrMo
42CrMo is the Chinese GB counterpart of 4140 and is widely specified on European and Chinese prints. CNC machined 42CrMo helical gear shafts, straight gear shafts, couplings and flanges are regular production items in our workshop.
Commonly CNC machined steel parts
Below are the part families we machine repeatedly. Each can be produced from carbon steel or alloy steel, per drawing or per sample, from one prototype to high-volume production.
Shafts and gear shafts
CNC machined steel shafts, stepped shafts, keyway shafts, spline shafts, CNC machined 4140 gear shafts and 42CrMo helical gear shafts, with OD/ID grinding where the print calls for a fine finish.
Bushings and sleeves
Custom CNC machined steel bushings, alloy shaft bushings, wear sleeves, spacer sleeves and stepped sleeves, in 1045, 40Cr, 42CrMo or bearing steel with reamed or honed bores.
Nuts and threaded parts
Custom CNC machined steel internal thread nuts, lock nuts, round nuts, threaded inserts, threaded fittings and standoffs, in metric, unified and special thread forms such as ACME or trapezoidal.
Gears and pinions
CNC machined steel spur gears, straight cylindrical bevel gears, helical gears, pinions, gear blanks and ring gears, hobbed or shaped and ready for subsequent hardening if required.
Flanges
CNC machined steel flanges, mounting flanges, bearing flanges, blank flanges and adapter flanges, with bolt-hole circles, counterbores and sealing faces machined to the drawing.
Brackets and mounting plates
Custom CNC machined steel motor brackets, support brackets, pivot brackets, base plates and mounting plates, often in 1020, Q235 or 4130 with milled faces and tapped holes.
Pins, dowels and studs
CNC machined steel dowel pins, alignment pins, clevis pins, taper pins, threaded studs and shafts with circlip grooves, produced to tight diameter and surface-roughness requirements.
Couplings and adapters
Rigid coupling halves, jaw coupling bodies, flange couplings, shaft adapters, reducer adapters and connector bodies in 1045, 4140 or 42CrMo, balanced and deburred as needed.
Hydraulic valve blocks
CNC machined 1045 hydraulic valve blocks and manifolds with cross-drilled galleries, tapped ports and nickel-plated or blackened surfaces for fluid-power equipment.
Housings and blocks
Bearing housings, gearbox housings, pump bodies, cylinder blocks, guide blocks and custom machined steel housings with bored pockets and precision locating faces.
Washers, spacers, collars
CNC machined steel spacers, shims, thrust washers, clamping collars, lock collars and setting rings, cut from tube, bar or plate depending on quantity and geometry.
Pulleys, rollers and wheels
Timing pulleys, V-belt pulleys, flat-belt pulleys, conveyor rollers, cam wheels and idler wheels, machined from 1045 or alloy steel with keyways and set-screw holes.
Grade-to-part machining coverage
The list below shows how steel grades and part names combine in real orders. Any of these combinations can be quoted directly from a drawing or a sample.
- CNC machined 1018 dowel pin
- CNC machined 1020 mounting bracket
- CNC machined 1035 shaft coupling
- CNC machined 1045 valve block
- CNC machined 1050 conveyor roller
- CNC machined 4130 frame fitting
- CNC machined 4140 gear shaft
- CNC machined 4340 drive spindle
- CNC machined 5140 hardened bushing
- CNC machined 40Cr transmission gear
- CNC machined 42CrMo helical gear shaft
- CNC machined 35CrMo threaded fitting
- CNC machined Q235 welded base plate
- CNC machined GCr15 bearing sleeve
- CNC machined steel stepped shaft
- custom CNC machined steel flange
- custom CNC machined steel lock nut
- CNC machined steel timing pulley
- custom CNC machined steel housing
- OEM machined steel component per print
Common surface treatments for machined steel parts
Rough-machined or finish-machined steel parts can be sent to a wide range of surface treatments for corrosion resistance, wear resistance, appearance or dimensional hardness. The treatment is always selected according to the note on the customer drawing.
Black oxide (blackening)
Alkaline black oxide finishing forms a thin black conversion layer on 1045, 4140 and alloy steel parts. It keeps dimensions almost unchanged, reduces glare and is usually sealed with anti-rust oil on shafts, nuts and fasteners.
Zinc plating
Electroplated zinc in white, blue-white or yellow chromate finish gives brackets, plates, pins and custom machined steel hardware economical outdoor corrosion protection; trivalent finishes are available on request.
Nickel plating
Electrolytic or electroless nickel plating delivers an even, wear-resistant layer, commonly used on CNC machined 1045 hydraulic valve blocks, spools, sleeves and parts with complex internal cavities.
Hard chrome plating
Hard chromium builds a very hard, low-friction surface on shafts, piston rods, rollers and bushings. Precision OD grinding after plating restores exact diameters and fine roughness.
Manganese phosphating
Manganese phosphate creates an oil-retentive dark gray layer that improves running-in behavior for gears, gear shafts, sliding parts and custom CNC machined steel components in moving assemblies.
Powder coating
Electrostatic powder coating in RAL colors protects exposed brackets, frames, covers and plates. Critical threads and mating bores are masked before coating to preserve fit.
Wet painting
Liquid primer plus topcoat is used on large welded-and-machined steel structures, machine frames and housings where film thickness and color must match the rest of an assembly.
Hot-dip galvanizing
Hot-dip zinc provides heavy-duty outdoor protection for Q235 and low-carbon steel brackets, mounting plates and structural parts; machining allowances are planned in advance for the zinc layer.
Sandblasting
Sand or glass-bead blasting removes scale and tool marks and produces a uniform matte surface before painting, powder coating or final assembly of CNC machined steel parts.
Polishing and brushing
Mechanical polishing, belt sanding and wire brushing improve surface appearance, remove burrs and blend machined transitions on rods, sleeves, handles and visible custom machined steel hardware.
Carburizing / case hardening
Low-carbon grades such as CNC machined 1018 and 1020 are carburized to obtain a hard wear-resistant shell over a tough core, ideal for pins, cams, gears and sprockets.
Nitriding and induction hardening
4140, 42CrMo, 5140 and 1045 parts can be nitrided or induction hardened for localized wear resistance on gear teeth, shaft journals and sliding ways, followed by finish grinding.
Machining and dimensional inspection
Steel parts are shaped on CNC milling and CNC turning equipment, then checked with optical and coordinate measuring instruments before packing. In-process checks happen after each major operation, and a final dimensional check follows the drawing.
CNC milling
Vertical machining centers mill faces, pockets, slots, keyways and complex contours on steel blocks, brackets, housings, flanges and valve bodies from solid bar, plate or forgings.
CNC turning
CNC lathes turn outside and inside diameters, grooves, chamfers and metric or unified threads on shafts, pins, bushings, sleeves, nuts and cylindrical OEM machined steel component families.
2D profile projector
The optical profile projector compares thread forms, radii, chamfer angles and small stamped or machined profiles against the drawing, which is especially useful for tiny custom machined steel hardware.
CMM testing
A coordinate measuring machine checks position, true position, flatness, perpendicularity and hole patterns on complex parts, alongside micrometers, bore gauges, thread gauges, height gauges, hardness testers and roughness testers.
From a single prototype to large-batch production
Steel CNC machining orders do not need to start large. The same workshop supports design validation, pilot runs and steady mass production, so customers can scale a component without changing supplier.
One-off and prototype
Steel part prototype machining and first-article builds for fit checks, assembly trials and trade-show samples. Bar ends and standard plate stock are used to keep one-off lead times short.
Small custom batch
Small-batch runs of custom machined steel hardware and replacement parts, with soft-jaw fixturing and standardized tooling to hold consistent dimensions across the run.
Repeat production
Recurring OEM machined steel component orders benefit from fixed fixtures, saved CAM programs, first-piece approval and in-process sampling at planned intervals.
Large-volume supply
High-volume production uses optimized cycle times, staged delivery and material heat-number traceability, keeping custom CNC machined steel parts uniform across monthly releases.
How an OEM steel machining order works
From the first drawing to the packed export carton, the workflow below is the same whether a customer needs carbon steel CNC machining in China or CNC machining alloy steel per drawing.
Drawings, samples and material selection
Customers send PDF or 3D drawings, or simply a physical sample when no print exists. We review dimensions, tolerances, thread specs, steel grade and required surface treatment, then point out any geometry that is difficult to machine before production starts. Material is purchased to the grade on the print, and heat numbers stay linked to the order for full traceability of every CNC machined steel part.
Machining route and tolerance control
Each part receives a process route: rough turning or milling, stress relief when needed, finish machining, grinding, gear cutting and final treatment. Metric and unified threads, fine bore tolerances, tight length control, keyways, splines and cross-holes are handled in-house, so a custom CNC machined steel shaft, block or gear does not depend on multiple outside vendors.
Inspection and measured records
First-article dimensions are checked against every drawing callout, followed by in-process checks and a final inspection using calipers, micrometers, bore gauges, thread rings and plugs, height gauges, a 2D profile projector and a CMM. Dimensional reports, material reports and surface-treatment records can follow the shipment for CNC machined 1045, CNC machined 4140, CNC machined 5140 or any other grade.
Packing and worldwide delivery
Finished steel parts are deburred, cleaned and coated with anti-rust oil, then packed in individual bags, labeled with part numbers and packed into export cartons or plywood cases suitable for sea or air freight. Neutral packing without supplier markings protects brands selling their own custom machined steel hardware and OEM machined steel component lines into Europe, North America, Russia, Pakistan, South Africa and other markets.