Overlock knife/blade compatible across the modern overlock family (JACK E4S/E5/C-series, Speedway SW6/SW7, and equivalents). Knives cross thread counts within the family. The Overlock Lower Knife (Part #21317002) is a genuine JACK original replacement part designed for JACK JK-E4S, C5, C6 and C7 series overlock machines. Manufactured to OEM specifications for precise fit and reliable performance. Equivalent Part Numbers JACK: 21317002 Compatible Machines This part fits the following industrial sewing machine models: JACK: JK-E4S series, C5, C6, C7, E4S-4, E4S-3-32R2, E4S-5-03, E4S-6-03, C7-4, C7-5, C7-3-02, E4S-3-02, C7-6-03/333 Urus, E5-3-32R2, E5-5-03, E3, C2, C3 SPEEDWAY: SW7-4D, SW7-5D, SW6-4D, SW6-3D, SW6-3D-32R, SW6-5D, SW6-6D JUKI: MO-6714, MO-6716, MO-6814, MO-6816 SIRUBA: 747, 757 PEGASUS: M700, EX5200 BROTHER: 3034 Technical Specifications Brand JACK Part Number 21317002 Part Type Knives Condition New – OEM Original Looking for a replacement overlock lower knife for your JACK JK-E4S or C5 overlock machine? This genuine OEM part ensures reliable performance and precise fit. Shop with confidence — all parts ship from Miami, FL. ⚠️ Compatibility Notice: Always verify your machine model and subclass number before ordering. Part numbers and compatibility are provided as a reference only. Supra Sewing is not responsible for purchases made without confirming compatibility with your specific machine. All sales on replacement parts are final.
