Custom Precision Alloy Steel CNC Turned Parts
Overview
Alloy steel CNC turning capabilities cover small pins through large shafts and discs up to 1250 mm in diameter and 2000 mm long. Small parts run continuously on a Jingshang 80 automatic lathe, while large-diameter parts use a Shenyang CK61125X2000 CNC lathe. Journal roundness can be controlled to 0.006 mm. The company is certified to ISO 9001, ISO 13485, IATF 16949 and GJB9001C. The minimum order is 1 piece, with prototypes in 3-7 days and standard orders in 10-15 days. Equipment listed for this machining service includes Shenyang CK61125X2000, Jingshang 80 automatic lathe, Mazak I-100S, DMG 80mono, Matsuura MX-520, Brother.
Key Capabilities
- Materials: 40Cr, 42CrMo; 20CrMnTi or 38CrMoAl when specified; other alloy steel grades reviewed by specification
- Tolerance: +/-0.003 mm (+/-0.00012 inch), IT5 or IT6 accuracy, +/-0.01 mm shaft/bore fits; h6/H7 available
- Surface Finish: Turned OD Ra 0.8 um; bored Ra 1.6 um; honed bore Ra 0.8 um; lapped Ra 0.4 um; polished Ra 0.2 um; precision polishing up to Ra 0.015 on selected critical areas
- GD&T: Roundness 0.006 mm, coaxiality 0.012 mm, shaft runout 0.012 mm, face runout 0.012 mm, cylindricity 0.011 mm / 1030 mm
- Max Size: Turning diameter 1250 x 2000 mm; milling travel 3000 x 1600 x 1400 mm
- Heat Treatment: Quench and temper, carburizing, or nitriding by grade and final condition, depending on grade, drawing and order requirements
- Thread: M1.4 to M220; NPT / BSP / G / PT pipe threads; go/no-go and ring gauge inspection
- Precision Limit: +/-0.003 mm dimensional, roundness 0.006 mm, hole-pattern position 0.015 mm (specific features, by drawing review)
Alloy Steel Bearing Journal Roundness and Cylindricity
Alloy steel bearing journals can achieve roundness of 0.006 mm and cylindricity of 0.011 mm / 1030 mm, suitable for journals on transmission and motor shafts. Shaft diameters are machined to ISO 286 fit grades, including h6/h7 or +/-0.005 mm. Journals requiring greater accuracy receive additional grinding after turning according to the drawing.
Alloy Steel Sleeve Bore Turning and Honing
Alloy steel sleeve bores can achieve H7/H8 or +/-0.006 mm tolerances, with a bored surface roughness of Ra 1.6 um. Hydraulic sleeves and sliding-fit bores can receive an additional honing operation to reduce roughness to Ra 0.8 um. The maximum bore diameter for turning is 1000 mm, accommodating large bearing housings and ring-shaped parts.
Large Diameter Alloy Steel Disc and Flange Turning
At a workpiece length of 2000 mm, the Shenyang CK61125X2000 supports a maximum turning diameter of 1250 mm. Large flanges and discs are normally scheduled using a conservative diameter limit of 1200 mm. After a large disc is clamped, its end face is aligned first; face runout can be controlled to 0.012 mm. External flange threads can be turned up to M220.
Small Alloy Steel Pins, Grooves and Knurling on Automatic Lathes
Alloy steel pins and small shafts under 100 mm are machined on a Jingshang 80 automatic lathe, with critical dimensional tolerances down to +/-0.003 mm. External threads start at M2.0, and retaining-ring grooves and tool-relief grooves have a minimum width of 0.5 mm. Straight and diamond knurling support a module range of 0.3-1.0, with chamfers from C0.1 to C3.0.
Specifications
| Product Name | Custom Precision Alloy Steel CNC Turned Parts |
|---|---|
| Manufacturer | XCM CNC (Shenzhen Xinchuangmeng Co., Ltd), Shenzhen, China |
| Factory Location | Shenzhen, Guangdong, China |
| Quality System | ISO 9001, ISO 13485, IATF 16949, GJB9001C |
| Machining Process | CNC turning |
| Material | Alloy steel |
| Material Grade | 40Cr, 42CrMo; 20CrMnTi or 38CrMoAl only when specified for the required treatment design |
| Tolerance | +/-0.003 mm on suitable precision features; IT5 or IT6; h6/h7 shaft fits, H7/H8 bores |
| Precision Tolerance | Roundness 0.006 mm, coaxiality 0.012 mm, shaft runout 0.012 mm, cylindricity 0.011 mm / 1030 mm |
| Surface Roughness | Turned Ra 0.8 um; bored Ra 1.6 um; honed Ra 0.8 um; lapped Ra 0.4 um; polished Ra 0.2 um |
| Surface Treatment | Nickel, zinc, or chrome plating, 3-20 um coating thickness, depending on grade, drawing and order requirements |
| Max Part Size | Turning diameter 1250 x 2000 mm; max bore 1000 mm |
| Inspection | Equipment: Hexagon Inspector Classic 06.08.06, Leader NCA8106, WanHao Rational VMS-3020G, TRIMOS 600L; Documents: Dimensional inspection report, CMM report, material certificate |
| Application | Transmission shafts, sleeves, gearbox input and output shafts, high-strength pins, hydraulic rods |
| Key Features | Journals, stepped diameters, sleeve bores, threads, retaining-ring grooves, knurling |
| Critical QC Requirements | Shaft and bore fits, roundness, coaxiality, shaft runout, turned or bored surface finish |
| MOQ | 1 piece |
| Typical Lead Time | Prototype 3-7 days; standard 10-15 days |
| Drawing Formats | STEP, IGES, STP, DWG, PDF with dimensions |
| Heat Treatment | Quench and temper, carburizing, or nitriding by grade and final condition, depending on grade, drawing and order requirements |
Applications
Transmission Input Shafts and Gear Blanks
Typical parts: Transmission input shaft, gear blank
Journals, stepped diameters and end faces on input shafts determine the mounting positions of bearings and drive components. Bores and end faces on gear blanks serve as datums for subsequent tooth machining. Machining priorities: journal roundness of 0.006 mm and gear-blank face runout of 0.012 mm.
Robot Joint Shafts and Servo Shafts
Typical parts: Robot joint shaft, servo motor shaft
The stepped journals on joint and servo shafts carry bearings, coupling components or rotors. Coaxial relationships between these journals directly affect assembly. Machining priorities: coaxiality of 0.012 mm and shaft diameter fits down to h6.
Construction Machinery Pins and Hydraulic Rods
Typical parts: Heavy-duty pin shaft, hydraulic rod
Pins transmit mechanism loads through fits between their outside diameters and mating holes. Hydraulic rods require long cylindrical working surfaces and connection threads at their ends. Machining priorities: turning lengths up to 2000 mm and end threads from M2.0 to M220.
Pump Shafts and Wind Turbine Drive Shaft Sleeves
Typical parts: Pump shaft, drive shaft sleeve
Pump shaft bearing seats and sleeve inside and outside diameters provide rotational support and mating fits. Machining priorities: H7 sleeve bores and Ra 0.8 um after honing, with large sleeves up to 1250 mm in diameter.
Why Choose Us
Quality Systems and Equipment for Shaft Fits
We operate under ISO 9001, ISO 13485, IATF 16949 and GJB9001C quality systems and machine parts using equipment from DMG, Mazak, Matsuura and Brother. CMMs, roundness testers and height gauges support dimensional verification.
Finish Turning and Grinding Evaluated for Journal Fits
Turning of journals, stepped diameters and sleeve bores is planned against the drawing. Specified precision fits receive further evaluation for grinding or honing within suitable bore diameter and length limits. Operations before and after heat treatment depend on the grade, condition and final dimensional requirements.
Tiered Equipment Strategy for Low-Cost CNC Machining, Quality-Assured Production
XCM CNC uses four tiers of CNC equipment from mainland China, Taiwan, Japan, and Europe and the United States. Rough turning and step machining with less demanding tolerances run on mainland Chinese or Taiwanese machines, while high-precision operations such as finish turning of h6 journals use imported machines such as DMG and Mazak. Equipment is selected for the accuracy each operation requires, avoiding machines with higher hourly costs for simple work and reducing machining costs while meeting drawing requirements.
Material Certificates and Grade Traceability
Material certificates for alloy steel bar stock such as 40Cr and 42CrMo can be supplied according to order requirements. SGS environmental compliance reports can also accompany delivery when needed. Cut stock is identified by part number to prevent grade mix-ups during machining. Customers can check grades directly against the certificates during incoming inspection.
Packaging and Shipping Matched to Long Shafts and Large Discs
Small parts use foam plus cartons. Long shafts and large-diameter discs use wooden crates, with journals protected and secured to reduce impact damage and bending during transit. Small batches can ship by DHL, FedEx or UPS, while heavy shafts can ship by sea freight.
FAQ
How do 40Cr and 42CrMo differ for a shaft project?
Both are candidate alloy structural steels. Selection depends on load, design requirements and the specified heat treatment condition; they should not be treated as automatically interchangeable. Provide the grade standard, material certificate requirements and final condition when requesting a quote.
How should bearing fits and shaft runout be specified on the drawing?
Specify journal fit grades such as h6 or h7 according to ISO 286, together with the runout measurement datum and total shaft length. Achievable runout depends on part length and fixturing and is evaluated during drawing review.
Can I request a single quote for small pins and large shafts?
Yes. They can be quoted in one order. Small pins are assigned to automatic lathes, while large-diameter shafts and discs use the CK61125X2000. Lead times for parts within the same order are evaluated individually according to complexity.
What happens if the first sample does not match the drawing?
Sample approval is required before batch production. Any nonconforming items in the sample dimensional inspection report are investigated and the process is adjusted. Batch production begins only after the revised sample is verified as acceptable.
Are turned parts for automotive projects produced under IATF 16949?
XCM CNC is certified to the IATF 16949 automotive quality management system and also holds ISO 9001, ISO 13485 and GJB9001C certifications. Specify the quality documents required for your project when requesting a quote.
How are long alloy steel shafts packed for export?
Long shafts are packed in wooden crates, with journals protected and the shafts secured inside to prevent movement and bending during transit. Shipping options include DHL, FedEx, UPS and sea freight.
What is the lead time for large-diameter turned parts?
Samples usually take 3-7 days and standard orders usually take 10-15 days. For large parts approaching 1250 mm in diameter or parts requiring heat treatment, lead time is evaluated against drawing complexity and order quantity.
What are the payment, shipping and packaging options?
Payment options are T/T, PayPal, Western Union. Shipping options are DHL / FedEx / UPS / Sea freight. Packaging options are Foam + carton / wooden crate.
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.
