# CNC Machined Shafts & Pins

> CNC turning is the primary process for shafts and pins because cylindrical features remain concentric in one setup. Live tooling adds flats, cross holes and key features; grinding is considered when bearing fits, surface finish or hardened material exceed the stable turning capability.

- HTML page: https://fabvector.com/custom-cnc-parts/cnc-machined-shafts-pins (Portuguese: https://fabvector.com/pt/custom-cnc-parts/cnc-machined-shafts-pins)
- Quote: https://fabvector.com/quote

## Typical applications

- Motor and gearbox shafts
- Pivot and clevis pins
- Hydraulic valve spools and rods
- Instrument and medical drive components

## Recommended manufacturing route

1. Establish the datum axis between centers or from the functional journal.
2. Turn diameters, shoulders and threads with maximum one-setup continuity.
3. Add flats, cross holes or key features with live tooling or a second operation.
4. Grind, finish and inspect fits or runout when the drawing requires it.

## Drawing and RFQ controls

| Control | Guidance |
|---|---|
| Datum axis | Reference runout and coaxial features to the journal that locates the shaft in service. |
| Shoulder relief | Provide a relief or compatible mating chamfer where a bearing must seat against a shoulder. |
| Slenderness | Long small-diameter shafts may need steady support, grinding or a straightness agreement. |
| Heat treatment | Define hardness, case depth and whether dimensions apply before or after heat treatment. |

## Recommended materials

- [alloy-steel-4140](https://fabvector.com/md/materials/alloy-steel-4140): Strong, heat-treatable shafts for industrial loads.
- [stainless-steel-17-4ph](https://fabvector.com/md/materials/stainless-steel-17-4ph): Strength plus corrosion resistance for loaded precision parts.
- [stainless-steel-303](https://fabvector.com/md/materials/stainless-steel-303): Efficient turning for moderate-duty corrosion-resistant pins.
- [titanium-grade-5](https://fabvector.com/md/materials/titanium-grade-5): High strength-to-weight for aerospace and medical mechanisms.

## Manufacturing processes

- [cnc-turning](https://fabvector.com/md/services/cnc-turning)
- [swiss-machining](https://fabvector.com/md/services/swiss-machining)
- [surface-grinding](https://fabvector.com/md/services/surface-grinding)
- [production-machining](https://fabvector.com/md/services/production-machining)

## Compatible finishes

- [black-oxide](https://fabvector.com/md/finishes/black-oxide)
- [electroless-nickel-plating](https://fabvector.com/md/finishes/electroless-nickel-plating)
- [passivation](https://fabvector.com/md/finishes/passivation)

## Inspection scope to define before production

- Micrometer or air-gauge results for fit diameters
- Runout, concentricity or position from the specified datum axis
- Thread gauges, hardness and surface finish when specified

## Buyer questions, answered

### What tolerance can be held on a turned shaft diameter?

FabVector publishes capability to +/-0.003 mm on selected turned diameters, but the achievable tolerance depends on length, diameter, material, heat treatment and inspection method. The drawing must identify only the fit diameters that need it.

### When is cylindrical grinding needed after turning?

Grinding is considered for hardened journals, fine surface finish, close roundness or diameter tolerance, and long bearing fits where turning alone is not stable enough.

### Can flats and cross holes be made in the same operation?

Often yes on a live-tooling lathe, depending on feature orientation and tool access. Consolidating operations can improve relationship to the turned datum and reduce handling.

### What quantity is suitable for custom shafts?

One-off replacements, prototypes and repeat bar-fed batches are all quotable. Batch economics improve when stock diameter, cutoff, workholding and inspection can be standardized.

## Related engineering guides

- [Swiss machining guide for small shafts](https://fabvector.com/blog/swiss-machining-small-precision-parts)
- [CNC turning capability](https://fabvector.com/services/cnc-turning)