If you don't the moving parts will start to rub against each other. HTey may eventually seize or wear out.
Because it has lots of moving parts that has to be able to move easily.
Using a sewing machine is a lot quicker and often neater than the much slower hand sewing. Some modern sewing machines are able to produce fancy stitching.
theory of sewing machine
sewing machine:) A sewing machine uses thread to fasten fabric together. A sowing machine plants seeds.
what is the function of the head of the sewing machine
A mechanical sewing machine.
The Sears Kenmore sewing machine model 1516 was produced in 1975. It is part of a long line of Kenmore sewing machines that were popular for their reliability and features during that era. This model is often sought after by vintage sewing machine enthusiasts.
the sewing machine brooklyn
what is the function of a pulley in a sewing machine
The Singer 2517 Sewing Machine is quiet.
What does the tension disc do on the sewing machine
If by "olden days" you're referring to prior to 1846 (when the sewing machine was invented), there was no sewing machine. All sewing was done by hand.