sentences:  They are also used for small-scale embroidery to provide steady tension, affixing the edges of the fabric with push-pins or a staple gun before beginning to sew, and then removing it from the frame when the work is complete.Strainer bar frames are usually in the shape of a rectangle, although shaped canvases are also possible.A stretcher frame constructed from strainer bars should not be confused with one constructed from stretcher bars.