{"product_id":"shuttle-hook-tension-spring-8611-bobbin-case-tension-singer-29k-29u-cobbler-machines","title":"Shuttle Hook Tension Spring #8611 - Bobbin Case Tension | Singer 29K, 29U Cobbler Machines","description":"\u003cp\u003eReplacement shuttle hook tension spring — Part #8611. A small, flexible metal plate that regulates bobbin thread tension on Singer 29K and 29U industrial shoe patcher (cobbler) machines. Sits on the outside of the shuttle hook and controls thread resistance as it exits the bobbin for balanced stitch formation on leather and heavy materials.\u003c\/p\u003e\u003cp\u003eThread constantly slides against this spring during sewing — over time it can develop a wear groove or lose springiness. Replacing it is a standard maintenance repair that restores consistent tension and stitch quality.\u003c\/p\u003e\u003ch2\u003eWhen to Replace\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eLoose or skipped stitches\u003c\/li\u003e\n\u003cli\u003eThread breakage\u003c\/li\u003e\n\u003cli\u003eVisible wear groove on the spring\u003c\/li\u003e\n\u003cli\u003eSpring has lost tension\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRelated Parts\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eRegulating Screw — Part #662 (adjust after installing new spring)\u003c\/li\u003e\n\u003cli\u003eShuttle Hook — Part #8603 (small bobbin)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSinger 29-1\u003c\/li\u003e\n\u003cli\u003eSinger 29K71, 29K73\u003c\/li\u003e\n\u003cli\u003eSinger 29K171, 29K171A\u003c\/li\u003e\n\u003cli\u003eSinger 29U171A, 29U173A\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"DMN","offers":[{"title":"Default Title","offer_id":42561563525218,"sku":"8611","price":6.0,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0767\/4681\/files\/IMG_2430.jpg?v=1771004228","url":"https:\/\/www.vintagesingerparts.com\/en-au\/products\/shuttle-hook-tension-spring-8611-bobbin-case-tension-singer-29k-29u-cobbler-machines","provider":"Central Michigan Sewing Supplies","version":"1.0","type":"link"}