No, it is not necessary that machine purchased is a capital good. It will depend upon its use.
- If a sewing machine is purchased by a tailor, then it is a fixed asset of the tailor and considered to be a capital good. But the same machine purchased by a consumer household is considered to be a durable use consumer goods.
- If a car purchased by a taxi driver as a taxi or if purchased by a firm for use in its business is a capital good. But the same car purchased by a consumer household is a durable use consumer goods.
Note: So, finally, the end user of a good determine, whether it is capital good or durable use consumer goods. If an end user of a durable goods is a producer, it is a capital good. If an end user of a durable goods is a consumer household, it is a durable use consumer goods. So, capital goods are only those durable goods which are used as producer goods, not as consumer goods.