Catalog words

A few drafting terms turn up across these sheets. Here is what each one means in a parts catalog, and what it stands for at home.

Assembly

A finished unit made of several parts, like a pump or a hub. On a household sheet, the whole job written on the top line.

Sub-assembly

A group of parts that is itself a unit inside a bigger one. At home, any line on the list that still hides a decision and needs its own sheet.

Exploded view

A drawing that shows the parts slid apart along their axis, so each one is visible and the order of assembly is clear.

Axis

The line the parts travel along when they come apart and go back together. On paper, the order of the day.

Callout

The number in a circle that points to a part. On the daily sheet, the circled number beside each piece of work.

Leader line

The thin stroke that connects a callout to its part, so nobody mistakes which number belongs to which piece.

Washer

A thin ring hidden under a nut or a bolt head, easy to forget. At home, the small preliminary step that holds a job up until it is found.

Bill of materials

The table that lists every part in a drawing with its number and quantity. The closest household cousin is the Friday review.