Part block
Custom shafts, pins and turned round parts
A shaft is the part where runout, straightness and diameter tolerance all have to be right at the same time, and where the length-to-diameter ratio decides whether the job is one operation or three. This block covers turned round parts from Ø1 mm pins to Ø200 mm shafts.
What we make in this block
| Diameter range | Ø1 mm – Ø200 mm (bar-fed to Ø32 mm, chucked above) |
|---|---|
| Length range | 3 mm – 1,200 mm |
| Diameter tolerance | ±0.01 mm turned; ±0.005 mm ground |
| Concentricity | 0.01 mm TIR on turned features; 0.005 mm on ground journals |
| Straightness | 0.02 mm per 100 mm after straightening |
| Surface finish | Ra 1.6 µm turned; Ra 0.4 µm ground |
| Materials | Stainless 303 / 304 / 316 / 17-4PH, alloy steel 4140, carbon steel 1045, aluminium 6061 / 7075, brass H62, titanium Gr2 / Gr5, POM, PEEK, PTFE |
| Slender work | Up to 6 × diameter with a tailstock; beyond that light passes and a steady rest |
Length-to-diameter ratio — what the ratio does to the process
| L/D ratio | Method | Held tolerance | Note |
|---|---|---|---|
| Up to 3 × D | Bar-fed turning | ±0.01 mm | No support needed |
| 3 – 6 × D | Tailstock or steady rest | ±0.01 mm | Centre hole required |
| 6 – 12 × D | Light passes, steady rest | ±0.02 mm | Straightness needs checking |
| Over 12 × D | Turning then grinding | ±0.005 mm on journals | Quoted case by case |
Processes, materials and finishes
Processes
- CNC turning
- Swiss screw machining
- Cylindrical grinding
- Centreless grinding
- Thread milling
- Keyway broaching
- Heat treatment
Materials
- Stainless 303 / 304 / 316 / 17-4PH
- Alloy steel 4140
- Carbon steel 1045
- Aluminium 6061 / 7075 / 2024
- Brass H62
- Titanium Gr2 / Gr5
- POM / PEEK / PTFE
Finishes
- Passivation
- Black oxide
- Electropolishing
- Chrome plating
- Nickel plating
- Hard chrome (wear journals)
- Anodizing (aluminium)
How it is quoted
| Minimum order | 100 pieces per part number (prototype quantities from 1) |
|---|---|
| Sample lead time | 7–10 days after drawing approval |
| Production lead time | 25–35 days after sample approval |
| Quote turnaround | Within 24 hours, with DFM feedback |
Specific part pages in this block
- Custom shafts
- Turned parts
- Custom pins
- Bushings and sleeves
- Spacers and standoffs
- Custom gears
- Impellers
- Custom knobs
Technical reading for this block
- CNC turning design rules
- CNC machining design rules
- Tolerance chart by process
- Fits and tolerances (H7/h6)
- Part weight calculator
- Tolerance stack-up
Questions
How long a shaft can you turn?
Up to 1,200 mm, but the practical limit is the length-to-diameter ratio, not the length. Beyond 6 × diameter the part needs a steady rest and light passes, and beyond 12 × diameter it is usually turned oversize and ground.
Can you hold a ground tolerance without a grinding operation?
Turned diameters hold ±0.01 mm reliably. For ±0.005 mm on a bearing journal we grind — it is a separate operation and a separate line on the quote.
Do you straighten shafts after heat treatment?
Yes. Heat treatment distorts, so shafts that need straightness are straightened and checked after treatment, then ground if the journal tolerance requires it.
Can you add a keyway, flat or cross hole?
Yes, but each one is a second operation on a lathe without live tooling. A single flat or cross hole on a short part is cheap; several features on a long slender shaft are not.
Send the drawing for shafts and pins
Quotes come back within 24 hours with DFM feedback. Minimum order 100 pieces per part number; samples from one piece.