Square Quartz Capillary with a Round Bore: Flat-Sided Positioning

Use and purpose · Specifications · In practice · Custom example · Buy or enquire

Use an outside face as the locating reference

A square section can rest against a defined face in a fixture. That face gives the installation a recognisable orientation and a reference from which another component can be positioned. The benefit comes from using the flat deliberately, rather than from the square shape alone.

The bore remains a separate feature. Its diameter describes the opening size; its position describes where that opening arrives relative to the support. A drawing that includes both is useful when a small passage must meet an adjacent part.

MQC391 configuration

Bring the bore and the receiver to the same datum

Imagine the square capillary seated against a flat stop. The receiving component can be located from that stop and an adjacent face, with the bore centre referenced to the same surfaces. This turns an outside contact into a meaningful channel position.

An end view explains that relationship. The side view then shows the supported length, exposed ends and approach of the receiving part. It also reveals whether a clamp sits too close to the connection to leave useful assembly space.

A small bore makes the end interface important

The outside section is much larger than the listed 0.127 mm opening. A connection that grips the body successfully can still cover the passage at its end. The contact area and receiving opening therefore matter independently of the holder fit.

This form is most useful when the flat-sided outside has a role in positioning. If the fixture is already built around a circular tube and no flat datum is needed, changing the outside profile may add another interface without solving the actual connection problem.

A custom example: locate the bore from a fixed flat stop

ILLUSTRATIVE DESIGN EXAMPLE

Suppose a fixture already uses a flat stop to position components. A proposed capillary can retain a square outside and dimension the round bore from that face and an adjacent reference. The mating component then uses the same datums, so the request concerns channel position as well as bore size.