Letter B in machine knitting is for Butt in a needle.

Letter B is for Buttons used for knitwear. This is clothes fastening object in the form of a tube or disc that has holes which are used to attach the object to the piece of clothing. Buttons can be made from plastic, wood and metal. The hole in a button can be two or more. Buttons come in different colours.

Letter B is Belt that is knitted on the knitting machine.

Letter B is also for Buttonhole or Buttonloop made on the knitting machine. This is a machine knitted loop, hole or slit which a button is passed through to fasten or secure the opening on the clothing or knitwear.

We have videos on Anino TV YouTube on how to knit a buttonhole on a single bed knitting machine.

Here are links to videos on Anino TV YouTube on how to machine-knit a buttonhole on a knitting machine

Buttonhole making on the Silver Reed SK280 Knitting Machine: https://youtu.be/i2ELKeXqW9g

Buttonhole making on the Silver Reed LK150 Knitting Machine: https://youtu.be/x5WPMflZw6Y