DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
PART / FICTIONAL EXAMPLE
Stepped spindle shaft
Three diameters turned from bar with a keyway flat and a threaded nose. Concentricity between the bearing seats is the whole specification.
How it is made.
Turned between centres so all three diameters share one axis, then the keyway is milled and the nose threaded. Turning between centres rather than in a chuck is what keeps the seats concentric.
Illustrative specification
- Bearing seats
- Example · Ø32 / Ø23 h6
- Nose thread
- Example · M20 × 1.5
- Overall length
- Example · 214 mm
- Concentricity
- Example · 0.015 mm
- Keyway
- Example · 6 × 6 mm
- Material
- Example · 42CrMo4
Every value above is an illustrative example for a fictional range. It is not a quotation, a capability statement or a measurement of any real part.
Which feature the datum is taken from.
The one the assembly is built from, which is not always the largest or the easiest to measure. Recording it on the drawing is what stops a supplier choosing a different one.
What it cannot confirm.
Whether the part survives its real use. That is established by testing under the real load, not by a first article on a bench.