Singer heavy duty using upholstery thread. Why is this happening? : r/sewing

Singer Universal Heavy Duty Machine Needles, Assorted Sizes - 5 count

Incraftables Leather Sewing Kit. Heavy Duty Stitching Craft Working Tools Set. Upholstery Repair Kit w/ Waxed Thread Cord, Needles, Tape, Awl, Scissors, Unpicker & Thimble for Beginner Hand Sewing

Topus Extra Strong Upholstery Repair Sewing Thread Kit and Heavy Duty Household Hand Needles, Including 7 Styles of Leather Canvas Sewing Needles and

Heavy Duty Upholstery Thread and Needles Kit for Hand Sewing, Including 3 Colors Extra Strong Nylon Thread and 2 Set Heavy Duty Hand Needles, Leather

Hand Sewing Needles Heavy Duty Thread Needle for Upholstery Carpet Leather Tool Leatherworking Stiching Sports Craft

0.6mm 50 Meters 2 Strands Extra Strong Nylon Thread Leather Upholstery Repair Heavy Duty Upholstery Thread for Hand Sewing - AliExpress

Upholstery Repair Sewing Kit, Heavy Duty Sewing Kit with Leather Sewing Needles, Curved Needles, Upholstery Thread, Sewing Awl, Seam Ripper, Leather Sewing Kit for Tent, Sofa, Canvas, Shoes, Carpet

Consew Premier 2339RB Heavy Duty Single Needle Upholstery Compound Walking Foot Sewing Machine w/ Table & Servo Motor

Home Sewing Assorted Needles - Juki Junkies

32 Yards Waxed Thread with Leather Hand Sewing Needles,150D Flat Sewing Waxed Thread and Leather Repair Needles for Home Upholstery Carpet Leather