Given a text, write a compressed version of it in a single sentence.

There are two major types of sewing machines used in garment assembly: the lockstitch and the chain-stitch machine. Each type feeds in separate threads above and below the fabric, and these two threads must be connected in some fashion to form a stitch.
The two major types of sewing machines used in garment assembly are the lockstitch and the chain-stitch. Each feed threads above and below the fabric. These threads connect to form a stitch.