How tight should a sensor housing drawing be?
Tight where the assembly depends on it - sealing face, coaxial diameter, locating feature - and general everywhere else. A deep drawn wall is a formed surface: its tolerance is a different class from a machined one, and over-tolerancing it adds tooling cost without adding function.
The three tolerance classes on one part
- Machined features: sealing faces, threads, bearing seats. This is where a fine callout belongs, including fine resolution on selected key features when the drawing confirms it.
- Drawn dimensional features: diameter, height, wall. Held by the die, checked by sampling per lot.
- General tolerance: everything the assembly does not depend on.
How to state it so it is enforceable
Give the datum scheme, name the acceptance method (drawing dimensions, gauge, CMM report or functional check), and say where the wall thickness is measured. An ambiguous tolerance is what turns a good part into a rejected lot.
Grade, wall thickness and tolerance are confirmed against the customer drawing. Batch heat treatment, slow wire cutting, passivation, electropolishing, plating, phosphating and coating are placed with qualified external processors and disclosed on the inspection plan. The quality system is ISO 9001:2015 with controls aligned to IATF 16949 requirements.