Wind thread on empty bobbins only – don’t wind additional thread onto partially wound bobbins, as this can cause stitch irregularities when you sew. Machine Size (15.5 x 6.25 x 12) Machine Weight (14.6) Box Size (18 x 8.5 x 13) Amps (0.7) Watts (84) Volts (120) Hz (60) Warranty (90 day / 2yr / 24yr) Find Complete Warranty Terms Here $7.99 $4.99 Save 38% 10pk Metal Bobbins, Class 15 #2518-A. Previous 1 2 3 Next. Watch video: Singer Heavy Duty 4423 4 Threading & Winding a Bobbin What Size Needles for Singer 4423? The Singer 4423 Heavy Duty parts and accessories on this page are guaranteed to fit the Singer 4423 Heavy Duty sewing machine or your money back. Contact Us: SingerOnline 176 North Main Street #100 Oberlin, Ohio 44074 (Cleveland) By Phone: 800-559-6729 By Email:info@singeronline.com These parts and accessories are guaranteed to fit your Singer 4423 (Heavy Duty) Sewing Machine. Bobbins For Domestic Singer Sewing Machines There are several Singer bobbins which … Bobbin Class (15 Transparent) SINGER or INSPIRA branded bobbins are recommended for best results. This sewing machine comes with a Singer Style 2020, size 90/14 needle preinstalled in the machine. Bobbin Tips & Hints Use only bobbins that are the same class/style as those that come with your machine – don’t substitute! NGOSEW for Singer Plastic Bobbins Heavy Duty 44S 4411, 4423, 4452, 5511, 5523, 5532 SINGER® branded bobbins are recommended for best results. NGOSEW for Singer Plastic Bobbins Heavy Duty 44S 4411, 4423, 4452, 5511, 5523, 5532 See Options $10.99 $9.99 Save 9% Bobbin Winder, Singer #K6A0555000. Use any Singer or Universale needle. Singer 10 pk Singer Transparent Bobbins … More Info ... $25.99 $22.99 Save 12% Bobbin Case, Singer #Q6A0764000.