Precision couplings
A torque-carrying rotating part: the coaxiality of the two bores matters more than the outside diameter.
Part family · Precision components
Earphone and earbud housings
Small, thin and curved: cosmetic consistency and the assembly shoulder are where parts usually fail.
What it is, and where it usually goes wrong
A small curved shell is judged by eye before it is judged by gauge. Two parts from the same batch have to look identical in texture and edge, and the shoulder that the driver or PCB seats against has to be at the same height in both halves.
How we machine it
- Machine both halves from the same set-up programme and the same stock batch, so the finish matches.
- Cut the assembly shoulder to a reference face, then check the pair assembled rather than separately.
- Handle with finger cots from the deburr stage — a fingerprint etched into a brushed face cannot be polished out.
- Use small tools with a light stepover on curved surfaces so the scallop does not read as a facet.
Where it is used
In-ear and over-ear cavities, acoustic module housings, portable audio shells.
What we check before it ships
- Shoulder height and the gap at the split line, assembled
- Surface texture against the approved sample
- Wall thickness at the nozzle and at the cable exit
- Thread or press-fit condition at the joint
Measured against your drawing and written on the inspection sheet that ships with the parts. First article reports are available on request.
What to send for a quote
- The 3D model, since these parts are defined by curvature rather than dimensions
- The finish and a reference sample if the texture must match an existing product
- The internal components that seat inside, with their tolerances
- Whether the joint is threaded, press-fit or glued
A STEP file plus a drawing is ideal; a PDF with tolerances also works. Quantity, material and finishing are enough to give you a real price instead of a range.
Questions we get on this part
Can you machine a housing this small at a sensible price?
Yes, but the cost is in the set-ups, not the material. Small shells usually need three or four operations plus a fixture, so the first article carries most of the cost and the per-piece price drops quickly after that.
Do you make the internal acoustic cavity too?
We machine the cavity as part of the shell, to the model you provide. Tuning the cavity is an acoustic design decision, so we hold the geometry and report the measured volume rather than adjust it ourselves.
Other precision components we machine
Connecting stems
A slender rod where straightness and the coaxiality of both threaded ends are the two things that decide fit.
Aluminium profile parts
Second-operation work from extrusion or plate, where datum choice and the anodising dimension chain are the risk points.
Send a drawing, get a price within 24 hours
STEP, IGES, DWG, PDF or a dimensioned sketch — plus material, quantity and finishing. We reply with a price and any questions in one message.