Precision couplings
A torque-carrying rotating part: the coaxiality of the two bores matters more than the outside diameter.
Part family · Precision components
Machined aluminium profile parts
Second-operation work from extrusion or plate, where datum choice and the anodising dimension chain are the risk points.
What it is, and where it usually goes wrong
These parts start as extrusion or plate and are finished by milling, drilling and tapping. The extrusion is never perfectly straight, so the first decision is which face becomes the datum — pick the wrong one and every hole inherits the bow of the profile.
How we machine it
- Face the datum side first and take a light cut; extrusion skin is harder and will deflect a cutter that is pushed.
- Machine from the datum in one direction, so hole positions are not affected by the profile twist at the far end.
- Allow for anodising growth on fits and on any dimension the customer measures after finishing.
- Deburr the cut ends of the profile before anodising, or the coating builds on the burr and looks like a defect.
Where it is used
Frame beams, mounting rails, heat-spreader plates, panels and brackets, module end caps.
What we check before it ships
- Datum face flatness and straightness along the length
- Hole pitch measured from the datum, at both ends
- Wall thickness after machining
- Fit at the assembly interface after anodising, not before
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 profile drawing or the extrusion code, if it is a standard section
- Which face is the datum in the customer's assembly
- Anodising specification and the classes that must fit after coating
- Length tolerance and how the part is cut from stock
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 our own extrusion?
Yes, and it is usually the better route — the section is already the shape you designed. Send the profile drawing and a cut length; we machine from your stock or source the section if the quantity justifies it.
How much does anodising change a dimension?
Type II anodising adds roughly half the coating thickness per surface, so a 20 µm coat moves a dimension by about 20 µm overall on a through dimension. It is small but not nothing on a fit, so we allow for it on the features you nominate.
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.
Earphone housings
Small, thin and curved: cosmetic consistency and the assembly shoulder are where parts usually fail.
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.