Shaft Specialists
CNC Shaft
Machining
Service
Custom CNC shaft machining for straight, stepped, splined, and threaded shafts with precision fits, keyways, and ground finishes for transmission, motor, and industrial applications.
Straight / Stepped / Splined / Threaded
h6 / h7 / k6 Fits
Keyways & Ground Finishes
Carbon / Stainless / Alloy Steel
Prototype to Production
Service Overview
Precision Shaft Machining for Fit-Critical Rotating Components
This is not a general turning page. This service is dedicated to functional shafts — components that carry bearings, transmit torque, accept keyways and splines, and must meet fit-class dimensional requirements on every journal.
We machine shafts from raw bar to finished functional part — including all fit diameters, shoulders, threads, keyways, splines, and ground surfaces specified on the drawing.
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Straight, Stepped, Splined & Threaded Shafts
Single-diameter bars to complex multi-feature shafts with combined shoulders, threads, keyways, and splines.
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Bearing Seats, Seal Seats & Fit Journals
Journal diameters held to h6, h7, or k6 fit classes with surface finish and concentricity verified.
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Keyways, Splines & Coupling Ends
Functional features machined complete — the shaft is ready to assemble, not half-finished.
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From Raw Bar to Finished Shaft
Turning, milling, grinding, and feature machining all managed in one workflow — one supplier, one quality system.
Core Value
Why Shaft Machining Requires More Than Standard Turning
A shaft is not just a cylinder. It is a functional assembly interface — and every journal, shoulder, and feature must work together.
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Challenges with Generic Turning Services
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Multiple fit diameters not individually controlledBearing seats, seal seats, and coupling journals each need different fit classes — generic turning treats them all the same.
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Keyway and spline features outsourced separatelyThe shaft arrives without functional features — keyways and splines sent out to another shop, adding lead time and fit risk.
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Runout and concentricity not verifiedShaft assembled into bearings and gears — but no verification that the shaft runs true across its full length.
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Ground finish not available on fit sectionsTurned finish alone does not meet the surface requirement for bearing seats or sealing surfaces — but grinding is not offered.
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How Our Shaft Machining Service Resolves This
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Every fit diameter machined and verified individuallyh6, h7, k6, g6 — each journal machined to its specified fit class and measured before the next feature is cut.
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Keyways, splines, threads, and cross holes done in-houseAll shaft features machined in one facility — no outsourcing, no additional lead time, no fit mismatch between suppliers.
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Concentricity and runout controlled and verifiedShaft checked for total runout across full length — critical for shafts running in bearings, gears, or high-speed assemblies.
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Cylindrical grinding available on fit sectionsGround finishes to Ra 0.4 µm on bearing seats, seal surfaces, and precision journals — applied where needed, not the entire shaft.
Shaft Types
Types of Shafts We Machine
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Straight Shafts
Single-diameter shafts for direct drive, simple supports, and guide applications.
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Stepped Shafts
Multi-diameter shafts with shoulders for bearing location, seal seats, and retaining rings.
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Splined Shafts
Involute and straight-sided splines for torque transmission in gearboxes and couplings.
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Threaded Shafts
External and internal threads — single and multi-start — for adjustment, locking, and drive screws.
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Keyed Shafts
Single or multiple keyways for pulleys, gears, and coupling engagement.
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Hollow Shafts
Through-bored shafts for weight reduction, fluid passage, or cable routing.
M
Motor Shafts
Precision shafts for electric motors with rotor seats, keyways, and encoder flats.
G
Gear Shafts
Integrated gear-and-shaft assemblies or mating shafts for gear train applications.
T
Transmission Shafts
Multi-feature shafts for power transmission with combined fits, splines, and threads.
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Precision Fit Shafts
Shafts where every journal is a fit-critical surface — h6, h7, k6, g6 per drawing specification.
Machining Features
Machining Features for Functional Shafts
Every feature machined in-house — the shaft ships ready to assemble.
Bearing Journals
Seal Seats
Shoulders
Retaining Grooves
External Threads
Internal Threads
Keyways
Splines
Flats
Cross Holes
Chamfers & Radii
End-Face Features
Metrology
Fits, Tolerances & Functional Shaft Surfaces
Shaft Fits
h6 / h7 / k6
ISO fit classes per drawing
Concentricity
0.01 mm TIR
Across full shaft length
Runout
0.015 mm
On fit journals
Ground Finish
Ra 0.4 µm
Bearing seats & seal surfaces
What We Control on Every Shaft
1
Fit-Critical Diameter Accuracy
Every journal machined and verified to the specified fit class — h6, h7, k6, g6 — with measurement recorded per section.
2
Bearing Seat Consistency
Bearing journals held to size and surface finish within the mating bearing specification — not just a general tolerance.
3
Concentricity & Runout
Total indicator runout measured across full shaft length to confirm the shaft will run true in its assembly.
4
Ground Finish Where Required
Cylindrical grinding applied selectively on bearing seats, seal seats, and precision fit sections — to the surface finish specified.
Material Selection
Materials for CNC Shaft Machining
1018
Carbon Steel 1018
Low-carbon · General-purpose shafts
1045
Carbon Steel 1045
Medium-carbon · Heat-treatable shafts
1215
Free-Cutting 1215
High-volume · Fast machining shafts
12L14
Free-Cutting 12L14
Leaded · Precision small shafts
4140
Alloy Steel 4140
Heat-treatable · High-strength shafts
4340
Alloy Steel 4340
Ultra-high strength · Critical shafts
8620
Alloy Steel 8620
Case-hardening · Wear-resistant shafts
52100
Bearing Steel 52100
Bearing-grade · High-hardness shafts
303
Stainless 303
Free-machining · Fast turnaround
304
Stainless 304
Corrosion resistant · General use
316
Stainless 316
Marine · Chemical · Medical shafts
17-4
17-4PH Stainless
High-strength · Aerospace shafts
Finishing
Surface Finish Options for Shaft Components
TN
Turned Finish
Standard CNC turned surface for non-critical shaft sections. Suitable for shoulders, spacer diameters, and non-contact surfaces where fit class is not specified.
GR
Ground Finish
Cylindrical grinding on bearing seats, seal surfaces, and precision fit journals. Applied selectively where turned finish does not meet the surface requirement — the most critical finish for functional shafts.
PL
Polished Journals
Mirror-polished fit sections for high-speed, low-friction, or sealing applications where surface roughness must be minimized beyond standard ground finish.
BO
Black Oxide
Mild corrosion protection with a dark, matte appearance. Common on carbon and alloy steel shafts for indoor industrial applications.
PS
Passivation
Chemical treatment for stainless steel shafts — enhancing the natural corrosion resistance of 303, 304, 316, and 17-4PH grades.
NP
Nickel Plating
Electroless nickel plating for uniform corrosion and wear protection on carbon and alloy steel shafts operating in harsh environments.
Applications
Typical Applications for CNC Machined Shafts
Functional shafts for rotating, transmitting, and load-bearing applications across all industries.
Motors
Electric & servo
Gearboxes
Transmission drives
Pumps
Centrifugal & gear
Conveyors
Drive & idler rolls
Automation
Actuators & drives
Robotics
Joint & actuator shafts
Couplings
Shaft-to-shaft connection
Agricultural
PTO & drive shafts
Transmission
Power transfer assemblies
Machinery
General industrial
h6/h7
Precision Fits
Ra 0.4µm
Ground Finish
10+
Shaft Types
24hr
Quote Turnaround
Service Comparison
CNC Shaft Machining vs General CNC Turning
Two services in the same facility — one broad, one specialized. Here's when each applies.
| CNC Shaft Machining | General CNC Turning | |
|---|---|---|
| Scope | Dedicated to functional shafts | All rotational parts — shafts, bushings, studs, spacers, flanges |
| Focus | Fits, journals, keyways, splines, runout | General cylindrical, conical, threaded, profiled parts |
| Typical Features | Bearing seats, seal seats, keyways, splines, coupling ends | OD/ID turning, threads, grooves, chamfers |
| Fit Classes | h6, h7, k6, g6 per drawing | Standard tolerances per drawing |
| Surface Finish | Ground finishes on fit sections (Ra 0.4 µm) | Turned finish standard (Ra 1.6 µm) |
| QC Emphasis | Runout, concentricity, fit verification | Dimensional accuracy per drawing |
| Best For | Transmission, motor, pump, and rotating assemblies | Broad range of cylindrical parts across all applications |
Quality Assurance
Quality Control for Precision Shaft Machining
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Diameter Inspection on Fit Sections
Every fit-critical journal measured individually — h6, h7, k6 diameters verified against drawing specifications with measurement recorded per section.
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Shoulder-to-Shoulder Checks
Axial distances between shoulders, retaining grooves, and thread starts verified to ensure correct bearing location and component positioning.
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Keyway & Spline Verification
Keyway width, depth, and position verified. Spline tooth profile and pitch checked against drawing or standard specification.
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Runout & Concentricity
Total indicator runout measured across full shaft length — confirming the shaft runs true for bearing, gear, and high-speed assembly applications.
Ra
Surface Finish Inspection
Surface roughness verified on ground journals, bearing seats, and seal surfaces — confirming the finish meets the mating component requirement.
MC
Material Certification
Material grade confirmed against order specification. Mill certificates with heat number available for projects requiring material traceability.
Workflow
How Our CNC Shaft Machining Works
1
Upload Drawing
Send STEP, IGES, DWG, or PDF with full dimensions, fit classes, and surface finish callouts.
2
Fit & Feature Review
Our engineers review all fit diameters, keyway specs, spline data, and functional requirements before quoting.
3
Quote & Process Plan
Detailed quote with machining strategy, grinding requirements, and lead time — within 24 hours.
4
CNC Shaft Production
Turning, milling, keyway cutting, threading, and grinding — all managed in one facility.
5
Inspection
Fit diameters, runout, concentricity, and surface finish verified. Reports available on request.
6
Delivery
Shafts packed with protection on fit surfaces. Material certs and inspection records included as required.
FAQ
Frequently Asked Questions
Everything about CNC shaft machining — types, features, fits, materials, and the difference from general turning.
We machine straight shafts, stepped shafts, splined shafts, threaded shafts, keyed shafts, hollow shafts, motor shafts, gear shafts, transmission shafts, and precision fit shafts. Parts range from simple single-diameter bars to complex multi-feature shafts with bearing journals, seal seats, keyways, splines, threads, and ground finishes — all produced from raw bar to finished functional shaft.
Yes. Stepped shafts with multiple diameters, shoulders, and transitions are a core capability. We produce involute and straight-sided splines, single and multi-start threads (both external and internal), and combinations of all three on a single shaft. Features are machined and verified to drawing specifications including fit class, pitch accuracy, and positional tolerances.
Yes. We machine keyways (single and multiple), Woodruff key seats, bearing journals, seal seats, and coupling ends to fit-critical tolerances. Journal diameters are held to h6, h7, or k6 fit classes as specified on the drawing, with concentricity and runout controlled to ensure proper assembly with bearings, seals, and mating components.
We machine shafts in carbon steel (1018, 1045), alloy steel (4140, 4340, 8620), stainless steel (303, 304, 316, 17-4PH), and specialty materials on request. Material selection depends on the application — we advise on the optimal grade during the engineering review based on load, environment, and hardness requirements.
Yes. We provide cylindrical grinding on bearing seats, seal surfaces, and precision fit sections where a turned finish alone does not meet the surface requirement. Ground finishes to Ra 0.4 µm and finer are available. Grinding is applied selectively to the features that require it — not the entire shaft — to control cost and lead time.
We routinely machine shaft diameters to h6, h7, g6, k6, and other ISO fit classes as specified on the drawing. Fit-critical sections are verified by measurement and recorded. For bearing seats and coupling fits, we confirm the achieved diameter and surface finish against the mating component specification.
CNC turning is a broad machining category covering all rotational parts — shafts, bushings, studs, spacers, flanges, and more. CNC shaft machining is a focused service specifically for functional shafts, with greater emphasis on fits, journals, keyways, splines, runout control, and the specific requirements of transmission and rotating assemblies.
Yes. We support shaft machining from single-piece prototypes through to full production quantities — all from the same facility with the same quality system. Prototypes receive the same engineering review, fit verification, and inspection as production shafts. There is no minimum order quantity.
Get a Quote
Send Your Drawing.
Get a Quote.
Every enquiry includes a DFM review — tolerance feasibility, material confirmation, and process approach confirmed before production starts. MOQ 1 piece.
24hr
Quote Response
MOQ 1
Prototypes OK
ISO
9001:2015
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DFM Review on Every Enquiry
Tolerance feasibility, fixturing strategy, and material confirmation. Specific, actionable feedback — not generic pushback.
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First Article Inspection — Standard
FAI report on every new run. Material certs and surface treatment certs included with every shipment.
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Same Process: Prototype to Production
Process plan from your prototype applies to production batches. No re-qualification when you scale.
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3 / 4 / 5-Axis CNC + Turning
Complex structural parts, shafts, housings, and transmission components. Metals and engineering plastics.
ISO 9001:2015
3/4/5-Axis Milling
CNC Turning
CMM Inspection
Global Delivery