{"product_id":"303-stainless-knurled-thumb-screws-m3-m4","title":"M3 \u0026 M4 303 Stainless Steel Knurled Thumb Screws – Hand Grip Bolts, Fully Threaded","description":"\u003cstyle\u003e\n  \/* 统一前缀 hdiy-，避免样式冲突 *\/\n  .hdiy-product-wrap {\n    margin: 0;\n    padding: 0;\n  }\n  .hdiy-product-wrap h2,\n  .hdiy-product-wrap h3 {\n    margin-top: 1.5em;\n    margin-bottom: 0.5em;\n    font-weight: 600;\n  }\n  .hdiy-product-wrap p {\n    margin-bottom: 1em;\n    line-height: 1.5;\n  }\n  .hdiy-features-list {\n    list-style: none;\n    padding-left: 0;\n  }\n  .hdiy-features-list li {\n    margin-bottom: 0.75em;\n    padding-left: 1.5em;\n    position: relative;\n    line-height: 1.4;\n  }\n  .hdiy-features-list li::before {\n    content: \" \";\n    position: absolute;\n    left: 0;\n    top: 0;\n  }\n  .hdiy-table-wrapper {\n    overflow-x: auto;\n    margin: 1.2em 0;\n  }\n  .hdiy-specs-table {\n    width: 100%;\n    border-collapse: collapse;\n    font-size: 0.95rem;\n    background: #fff;\n    min-width: 300px;\n  }\n  .hdiy-specs-table th,\n  .hdiy-specs-table td {\n    border: 1px solid #ddd;\n    padding: 10px 12px;\n    text-align: left;\n    vertical-align: top;\n  }\n  .hdiy-specs-table th {\n    background-color: #f5f5f5;\n    font-weight: 600;\n    width: 35%;\n  }\n  .hdiy-faq-item {\n    margin-bottom: 1.25rem;\n    border-bottom: 1px solid #eee;\n    padding-bottom: 0.75rem;\n  }\n  .hdiy-faq-question {\n    font-weight: 700;\n    margin-bottom: 0.35rem;\n    font-size: 1rem;\n  }\n  .hdiy-faq-answer {\n    margin-top: 0;\n    line-height: 1.45;\n    color: #2c2c2c;\n  }\n  @media (max-width: 640px) {\n    .hdiy-specs-table th,\n    .hdiy-specs-table td {\n      padding: 8px 10px;\n    }\n  }\n\u003c\/style\u003e\n\n\u003cdiv class=\"hdiy-product-wrap\"\u003e\n  \n  \u003c!-- Product Overview --\u003e\n  \u003ch2\u003e🔧 Product Overview: Knurled Thumb Screws – 303 Stainless Steel, M3 \u0026amp; M4 Hand Grip Bolts\u003c\/h2\u003e\n  \u003cp\u003eFor tool‑less fastening that combines a comfortable, non‑slip grip with excellent corrosion resistance, these 303 stainless steel knurled thumb screws are an ideal choice. The domed, knurled head provides a secure surface for hand tightening and loosening – no screwdriver or wrench needed. Manufactured to precise dimensions (see table), they feature a full thread with standard coarse metric pitch (M3x0.5, M4x0.7). The robust 303 stainless steel construction offers good corrosion resistance and strength, making them suitable for both indoor and outdoor applications. Perfect for automotive trim, machinery access panels, 3D printers, camera rigs, and any DIY project where hand‑operated fasteners are preferred.\u003c\/p\u003e\n  \n  \u003c!-- Key Features List --\u003e\n  \u003ch2\u003e✨ Why These 303 Stainless Steel Knurled Thumb Screws Are a Workshop Essential\u003c\/h2\u003e\n  \u003cul class=\"hdiy-features-list\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e303 stainless steel construction\u003c\/strong\u003e – Offers excellent corrosion resistance, good machinability, and moderate strength. Ideal for applications where rust is a concern.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eKnurled domed head for tool‑less grip\u003c\/strong\u003e – Diamond knurl pattern provides a secure, non‑slip surface for hand tightening and loosening – no tools required.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAvailable in M3 and M4 metric sizes\u003c\/strong\u003e – Common diameters for electronics, automotive trim, light machinery, and DIY projects.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFully threaded, coarse metric pitch\u003c\/strong\u003e – Standard threads (M3x0.5, M4x0.7) run the entire length for maximum grip and easy nut engagement.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePrecision dimensions per supplied spec\u003c\/strong\u003e – Head diameter (A) and knurled collar diameter (B) meet the values shown in the table.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWide applications\u003c\/strong\u003e – Automotive (carbolts), machinery access panels, 3D printer bed leveling knobs, camera rigs, electronic enclosures, and general DIY.\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \n  \u003c!-- Specifications Table (including dimensional data from image) --\u003e\n  \u003ch2\u003e📏 Technical Specifications – 303 Stainless Knurled Thumb Screws (M3 \u0026amp; M4)\u003c\/h2\u003e\n  \u003cdiv class=\"hdiy-table-wrapper\"\u003e\n    \u003ctable class=\"hdiy-specs-table\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n\u003cth\u003eThread Size (d)\u003c\/th\u003e\n\u003cth\u003eThread Pitch (p)\u003c\/th\u003e\n\u003cth\u003eHead Diameter (A) max\u003c\/th\u003e\n\u003cth\u003eKnurled Collar Diameter (B) max\u003c\/th\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eM3\u003c\/th\u003e\n\u003ctd\u003e0.5mm\u003c\/td\u003e\n\u003ctd\u003e9.10mm\u003c\/td\u003e\n\u003ctd\u003e7.10mm\u003c\/td\u003e\n\u003ctd\u003e303 Stainless Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eM4\u003c\/th\u003e\n\u003ctd\u003e0.7mm\u003c\/td\u003e\n\u003ctd\u003e9.10mm\u003c\/td\u003e\n\u003ctd\u003e7.10mm\u003c\/td\u003e\n\u003ctd\u003e303 Stainless Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n  \u003cp\u003e\u003cem\u003eNote: Length is measured from underside of head to tip (thread length). Various lengths available – select from options. All screws are fully threaded. Dimensions based on provided specification.\u003c\/em\u003e\u003c\/p\u003e\n  \n  \u003cdiv class=\"hdiy-table-wrapper\"\u003e\n    \u003ctable class=\"hdiy-specs-table\"\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eKnurled Thumb Screws (Hand Grip Bolts)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial Grade\u003c\/th\u003e\n\u003ctd\u003e303 Stainless Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eDrive Style\u003c\/th\u003e\n\u003ctd\u003eHand grip (toolless)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHead Style\u003c\/th\u003e\n\u003ctd\u003eDomed knurled head\u003c\/td\u003e\n        \u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cth\u003eThread Type\u003c\/th\u003e\n\u003ctd\u003eFully threaded, coarse metric\n        \u003c\/td\u003e\n\u003ctr\u003e\n\u003cth\u003eLength Options\u003c\/th\u003e\n\u003ctd\u003eSelect from dropdown (various lengths available)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eLength Measurement\u003c\/th\u003e\n\u003ctd\u003eUnder head – from underside of head to tip (head not included)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \n    \n  \u003c\/div\u003e\n  \n  \u003c!-- Frequently Asked Questions --\u003e\n  \u003ch2\u003e❓ FAQs – 303 Stainless Knurled Thumb Screws\u003c\/h2\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 What is the difference between 303 and 304 stainless steel?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003e303 stainless contains added sulfur for improved machinability, making it easier to produce precision parts. It has slightly lower corrosion resistance than 304 but is still excellent for most indoor and light outdoor applications. For saltwater or heavy chemical exposure, 316 stainless is recommended.\u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 Are these screws fully threaded? How is length measured?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003eYes – they are fully threaded from under the head to the tip. Length is measured from the underside of the domed head to the tip (head not included). For example, an M4 x 20mm screw has a 20mm threaded shank.\u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 What are the head dimensions (A and B) shown in the table?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003eA is the overall head diameter (9.10mm for M3\/M4). B is the diameter of the knurled collar section (7.10mm). These dimensions ensure a consistent, comfortable grip and proper fit in your application.\u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 Can I use these screws with nuts, or are they for tapped holes only?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003eThese are standard machine screws – they work with matching M3 or M4 nuts or in pre‑tapped holes. For through‑hole applications, use a nut on the back side. The knurled head is for hand grip only – do not use tools on the knurling.\u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 What lengths are available for M3 and M4?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003eWe offer various thread lengths – please select from the dropdown options. Typical ranges: M3: 6–30mm, M4: 8–40mm. If you need a specific length not listed, contact us for a custom quote.\u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"hdiy-faq-item\"\u003e\n    \u003cdiv class=\"hdiy-faq-question\"\u003e🔸 Are these screws magnetic?\u003c\/div\u003e\n    \u003cdiv class=\"hdiy-faq-answer\"\u003e303 stainless steel is generally non‑magnetic in its annealed state, but cold working (like thread rolling) can make it slightly magnetic. A light magnetic response is normal and does not affect corrosion resistance.\u003c\/div\u003e\n  \u003c\/div\u003e\n\u003c\/div\u003e","brand":"HomeDIYer","offers":[{"title":"M3*6mm \/ 1","offer_id":52292601413906,"sku":"GYWXWJLWJ00159x1","price":1.75,"currency_code":"USD","in_stock":true},{"title":"M3*8mm \/ 1","offer_id":52292601446674,"sku":"GYWXWJLWJ00160x1","price":1.75,"currency_code":"USD","in_stock":true},{"title":"M3*10mm \/ 1","offer_id":52292601479442,"sku":"GYWXWJLWJ00161x1","price":1.75,"currency_code":"USD","in_stock":true},{"title":"M3*12mm \/ 1","offer_id":52292601512210,"sku":"GYWXWJLWJ00162x1","price":1.75,"currency_code":"USD","in_stock":true},{"title":"M3*14mm \/ 1","offer_id":52292601544978,"sku":"GYWXWJLWJ00163x1","price":1.75,"currency_code":"USD","in_stock":true},{"title":"M3*16mm \/ 1","offer_id":52292601577746,"sku":"GYWXWJLWJ00164x1","price":1.84,"currency_code":"USD","in_stock":true},{"title":"M3*20mm \/ 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