CoreSpunThere are two types of core spun sewing thread. They are cotton wrapped poly core, (D-Core) and the poly wrapped poly core, (Perma Core).

Perma Core is a premium poly wrapped poly core spun product that delivers a higher seam strength and sewing performance over spun products, allowing for smaller thread sizes. This helps minimize seam puckering and needle cutting. Perma Core is produced by spinning polyester around a high tenacity continuous-filament core to form a single yarn. Then these yarns are twisted together to make one thread. Because Perma Core is 100% polyester, it offers good chemical and abrasion resistance and superior colorfastness in the finished seam. It is available in a full range of colors and sizes.

D-Core is premium cotton wrapped poly core product that is produced like Perma Core except the high tenacity yarn is wrapped with cotton staple instead of polyester. Because of the cotton wrap, it offers better needle heat resistance than Perma Core and provides a “washed down” look during garment-washing processing, giving a soft, low-sheen appearance. Because of the high tenacity continuous-filament core, D-Core also offers a high seam strength which allows for small thread sizes. D-Core is also available in a full range of colors and sizes.

Perma Core Size Chart

Application Tex Size Metric Size Minimum Needle Size
Extra Light Wt. 18 160 65
Light Weight 24 120 70
30 80 80
Medium Wt. 40 75 90
50 60 100
60 50 110
Heavy Wt. 80 36 120
105 27 125
120 25 130
Extra Heavy Wt. 135 20 140
150 18 160
180 14 180
240 12 200
300 8 230

D-Core Size Chart

Application Tex Size Metric Size Minimum Needle Size
Light Weight 24 120 70
35 80 80
Medium 40 40 90
50 60 100
60 50 110
Heavy 80 36 120
105 27 125
120 25 130
Extra Heavy 135 20 140
150 18 160
180 14 180
240 12 200
300 8 230
350 7 230