CNC Machined Shafts
Shafts transmit torque and rotate at speed, so concentricity and bearing-journal tolerance matter more than almost any other feature. We turn and grind precision shafts in steel, stainless, and titanium for motion and power-transmission applications.
What is a CNC machined shafts?
A shaft is a rotating part that transmits power or motion, supported by bearings along its length. CNC turning produces the cylindrical body, shoulders, threads, and keyways; grinding finishes the bearing journals to a precise diameter and surface finish. The defining quality requirements are runout (concentricity between journals) and diameter tolerance at each bearing seat.
Common materials
Free-machining 303 for general shafts; 304 where more corrosion resistance is needed.
High strength and good fatigue life for drive and transmission shafts, often heat-treated.
High strength plus corrosion resistance for pump and aerospace shafts.
Lightweight, high-strength shafts for aerospace and medical drives.
Typical tolerance
±0.01 mm
Bearing journals are commonly held to h6/h7 with ground finishes (Ra 0.4 µm or better) and concentricity controlled with GD&T runout callouts.
How we machine them
Produces the shaft body, shoulders, chamfers, threads, and grooves in one operation.
Adds keyways, flats, and cross-holes without a second setup.
Finishes bearing journals to tight diameter and fine surface finish.
Design tips that lower cost
Control runout, not just diameter
A shaft can be perfectly round at each journal but still vibrate if the journals aren't concentric. Specify total runout between bearing seats with a GD&T callout — that's what governs smooth running.
Add relief grooves at shoulders
Where a journal meets a shoulder, a small undercut (relief groove) lets the grinding wheel run out cleanly and removes the stress riser of a sharp internal corner.
Use standard keyway and thread sizes
Standard keyway widths and thread pitches use stock tooling. Custom dimensions add tool lead time and cost with no functional gain.
Plan heat treatment into the tolerance
Heat-treating a steel shaft moves dimensions. We rough-turn, heat-treat, then finish-grind the journals so the final tolerance is correct after hardening.
Industries we machine shafts for
Shafts — frequently asked
How concentric can you hold the bearing journals on a shaft?
With grinding and between-centers setup we routinely hold total runout under 0.01 mm between journals, and tighter on critical spindle work.
Can you machine splined or keyed shafts?
Yes — keyways are milled in a turn-mill setup, and we produce involute and parallel splines to your drawing or mating-part spec.
Do you grind shafts after heat treatment?
Yes. For hardened steel shafts we rough-machine soft, send out for heat treat, then finish-grind the bearing journals to final size — the standard sequence for dimensional accuracy.
Need shafts machined?
Upload your drawing — our engineers review it for DFM and send a real quote within 24 hours. No minimum order.
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