{"id":49052,"date":"2026-10-29T13:32:25","date_gmt":"2026-10-29T12:32:25","guid":{"rendered":"https:\/\/nauticspares.com\/?post_type=product&#038;p=49052"},"modified":"2026-10-29T16:52:01","modified_gmt":"2026-10-29T15:52:01","slug":"stainless-steel-threaded-boat-deck-insert-m8-316l-cm3368","status":"publish","type":"product","link":"https:\/\/nauticspares.com\/en\/product\/stainless-steel-threaded-boat-deck-insert-m8-316l-cm3368\/","title":{"rendered":"Stainless steel threaded boat deck insert M8 &#8211; 316L &#8211; CM3368"},"content":{"rendered":"<h2>Description of the stainless steel threaded boat deck insert M8 &#8211; 316L &#8211; CM3368<\/h2>\n<p>The <strong>CM3368 stainless steel threaded boat deck insert M8<\/strong> is a sealed fixing solution engineered for decks and cockpit soles. Machined from <strong>316L marine-grade stainless steel<\/strong>, it creates a durable M8 female thread in sandwich or solid deck structures, where a standard screw would gradually loosen or allow water to seep into the core.<\/p>\n<p>Its external self-tapping profile cuts its own thread as it is driven in, while the countersunk head finishes <strong>flush with the deck surface<\/strong>. The closed design, combined with a bead of adhesive or sealant during fitting, prevents water ingress into the laminate and greatly extends the service life of the installation. The insert is driven with a 7 mm Allen key through its internal hex socket, and offers an 18 mm usable thread depth for the M8 fixing screw.<\/p>\n<p>At Nauticspares, we primarily supply these inserts for anchoring our <strong>4S seats<\/strong> to the deck. With its larger M8 thread, the CM3368 is the natural choice for more heavily loaded fittings: deck hardware, mooring cleats, padeyes, ski towers, rollbars, biminis, suspended seats or swim ladders. It is a dependable solution for yacht builders, refit yards and owners looking for clean, long-lasting fixing points on board.<\/p>\n<h3>Specifications<\/h3>\n<ul>\n<li><strong>Type:<\/strong> Sealed self-tapping threaded insert<\/li>\n<li><strong>Material:<\/strong> 316L stainless steel<\/li>\n<li><strong>Internal thread:<\/strong> M8<\/li>\n<li><strong>Usable thread depth:<\/strong> 18 mm<\/li>\n<li><strong>Overall length (L):<\/strong> 25 mm<\/li>\n<li><strong>Head diameter (\u00d8A):<\/strong> 20 mm \u2013 countersunk, flush finish<\/li>\n<li><strong>Spigot diameter (\u00d8B):<\/strong> 14 mm<\/li>\n<li><strong>Drive:<\/strong> Internal hex socket \u2013 7 mm Allen key<\/li>\n<li><strong>Recommended deck thickness:<\/strong> 20 mm minimum<\/li>\n<\/ul>\n<h3>Installation \/ Maintenance<\/h3>\n<h4>Installation:<\/h4>\n<ul>\n<li>Mount the inserts on the fitting jig, place them on their future location and lightly mark the surface: the drilling positions are now defined.<\/li>\n<li>Drill a pilot hole first, then drill to the specified diameter.<\/li>\n<li>Coat both the insert and the hole with adhesive or marine sealant, then screw the insert in with a 7 mm Allen key until it sits flush.<\/li>\n<li>Allow the adhesive to cure fully before mounting the accessory.<\/li>\n<li>A deck or panel thickness of at least 20 mm is recommended for optimal hold.<\/li>\n<\/ul>\n<h4>Maintenance:<\/h4>\n<ul>\n<li>No specific maintenance is required: 316L stainless steel withstands salt spray and the marine environment.<\/li>\n<li>Periodically check the tightness of the fixing screws and the condition of the seal around the fitting.<\/li>\n<\/ul>\n<div data-class=\"product-pros-cons-section\">\n<h3>Our review<\/h3>\n<div data-class=\"product-pros-cons-wrapper\">\n<div data-class=\"product-pros_cons product-pros\">\n<h4>\u2714\ufe0f Pros :<\/h4>\n<ul data-class=\"pros-cons-list\">\n<li>316L stainless steel, highly resistant to corrosion at sea.<\/li>\n<li>M8 thread suited to heavier deck fittings.<\/li>\n<li>Sealed fitting that protects the deck core from water ingress.<\/li>\n<li>Flush finish for a clean, snag-free deck.<\/li>\n<\/ul>\n<\/div>\n<div data-class=\"product-pros_cons product-cons\">\n<h4>\u274c Cons :<\/h4>\n<ul data-class=\"pros-cons-list\">\n<li>Requires a deck thickness of at least 20 mm.<\/li>\n<li>Permanent installation, bonded in place.<\/li>\n<li>Curing time needed before the accessory can be fitted.<\/li>\n<\/ul>\n<\/div>\n<div data-class=\"product-pros_cons product-conclusion\">\n<h3>Conclusion<\/h3>\n<p>The <strong>CM3368<\/strong> is the right choice if your fittings call for M8 screws and you need robust, watertight anchoring points on a deck at least 20 mm thick \u2013 for seats, cleats, rollbars or bimini frames. Its 316L construction ensures long-term reliability in a marine environment. For lighter hardware using M6 screws, the CM3367 version offers a more compact head; for thinner panels, a through-bolted fixing with a backing plate will be more appropriate.<\/p>\n<\/div>\n<div data-class=\"product-pros_cons product-good-to-know\">\n<h3>Good to Know<\/h3>\n<ul data-class=\"pros-cons-list\">\n<li>Primarily used to anchor our 4S seats to the deck.<\/li>\n<li>Use a marine-grade adhesive or sealant to guarantee watertightness.<\/li>\n<li>Pair with A4 (316) stainless steel screws to avoid galvanic corrosion.<\/li>\n<li>Also available in M6 under reference <a href=\"https:\/\/nauticspares.com\/en\/product\/stainless-steel-threaded-boat-deck-insert-m6-316l-cm3367\/\" title=\"CM3367\">CM3367<\/a>.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The <strong>CM3368<\/strong> is an <strong>M8 threaded insert<\/strong> in <strong>316L stainless steel<\/strong>, designed to create strong, sealed fixing points in boat decks.<\/p>\n<p>With its self-tapping profile and countersunk head, this <strong>deck insert<\/strong> sits flush once screwed in, offering a clean and durable anchoring point for heavier deck fittings.<\/p>\n<p>Ideal for mounting deck hardware, cleats, bimini fittings or <strong>4S seats<\/strong> on board motor boats, sailing yachts and work boats.<\/p>\n","protected":false},"featured_media":49055,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[1280],"product_cat":[54,122,93],"product_tag":[1281],"class_list":["post-49052","product","type-product","status-publish","has-post-thumbnail","product_brand-nauticspares","product_cat-seat-suspensions","product_cat-mechanical","product_cat-spare-parts","product_tag-nauticspares","first","instock","taxable","shipping-taxable","purchasable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/product\/49052","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/comments?post=49052"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/media\/49055"}],"wp:attachment":[{"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/media?parent=49052"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/product_brand?post=49052"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/product_cat?post=49052"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/nauticspares.com\/en\/wp-json\/wp\/v2\/product_tag?post=49052"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}