Note: Bonded Polyester upholstery threads size #69 and up were designed for walking foot upholstery machines sewing primarily on exterior fabrics with size 20-25 needles. Juki, Brother, Consew, Pfaff, Reliable, Tacsew, Yamata and Singer high speed straight stitch industrial power stand machines and portable home sewing machines were designed for regular home sewing and quilting threads sewing primarily on interior fabrics with size 9-19 needles. Not to say that it cannot be done with the same 1/2-3/4HP motors, but the top thread diameter clearances around the rotary hook may be too close to prevent jamming with upholstery threads, even with size 19 needles. We recommend using bonded nylon and polyester upholstery threads only with portable walking foot and industrial sewing machines. John Douthat, Owner & Tech, AllBrands.com