{"id":92,"date":"2025-10-19T02:28:10","date_gmt":"2025-10-19T06:28:10","guid":{"rendered":"https:\/\/kyleward.ca\/?page_id=92"},"modified":"2025-10-19T11:09:24","modified_gmt":"2025-10-19T15:09:24","slug":"fasteners-101-bolts-screws-and-what-makes-them-work","status":"publish","type":"page","link":"https:\/\/kyleward.ca\/?page_id=92","title":{"rendered":"Fasteners 101 &#8211; Bolts, Screws and What makes them work"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Threaded Fasteners<\/h2>\n\n\n\n<p>This post is to support your learning before we meet synchronously to recap what you&#8217;ve discovered in regards to bolts and screws. Please take some time to read through, click on some linked resources, test your knowledge with the interactive animation, and if you&#8217;d like &#8211; try some of these new skills around your house!<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">What exactly is a fastener &#8211; and why does it matter?<\/h3>\n\n\n\n<p>Everyday objects, machines, furniture, vehicles\u2014the unseen force holding much of it together is fasteners. The term fastener broadly covers screws, bolts, nuts, rivets and more, but for our purposes we will focus on <strong>threaded fasteners<\/strong>\u2014the ones with helical grooves that clamp material together.<\/p>\n\n\n\n<p>If you want a quick visual overview before diving in, check out this short \u201cfasteners 101\u201d video:<\/p>\n\n\n\n<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/kVN_thmmX3o?si=nX1G3keq-agA--5C&amp;start=44&#038;end=288\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n\n\n<p>Understanding fasteners isn\u2019t just about picking the right size\u2014it\u2019s about knowing how they work, how they engage, how they hold, and what happens if you choose the wrong one.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Bolt vs. Screw &#8211; Clearing the confusion (kind of)<\/h3>\n\n\n\n<p>One of the first places confusion arises is whether a given piece of hardware is called a <strong>bolt<\/strong> or a <strong>screw<\/strong>. Many people use the terms interchangeably, but there are subtle (and important) differences.<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"500\" src=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/bolt-screw-difference-e1643094533950.jpg\" alt=\"\" class=\"wp-image-96\" style=\"width:379px;height:auto\" srcset=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/bolt-screw-difference-e1643094533950.jpg 800w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/bolt-screw-difference-e1643094533950-300x188.jpg 300w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/bolt-screw-difference-e1643094533950-768x480.jpg 768w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/bolt-screw-difference-e1643094533950-432x270.jpg 432w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/figure>\n\n\n\n<p class=\"has-text-align-center\"><strong>Technically Correct<\/strong><\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault-1024x576.jpg\" alt=\"\" class=\"wp-image-97\" srcset=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault-1024x576.jpg 1024w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault-300x169.jpg 300w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault-768x432.jpg 768w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault-480x270.jpg 480w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/maxresdefault.jpg 1280w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"has-text-align-center\"><strong>Practical Terminology<\/strong><\/p>\n<\/div>\n<\/div>\n\n\n\n<p>According to standard references, a bolt is typically defined as <em>\u201can externally threaded fastener designed for insertion through holes in assembled parts and normally intended to be secured by a nut.\u201d<\/em> Meanwhile, a screw is <em>\u201can externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a pre-formed internal thread or of forming its own thread, and of being tightened or released by torquing the head.\u201d<\/em><\/p>\n\n\n\n<p>Still confused? I&#8217;ve got more for you. In practice the line blurs &#8211; some screws use nuts, some bolts drive into tapped holes, some dart straight into unthreaded material, etc. A great video that walks through this nuance:<\/p>\n\n\n\n<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/-HaByqLxxMo?si=oWW4XGhYvjOYaVk6\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n\n\n<p>Here are the key things you should take away from bolts vs screws:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A \u201cbolt\u201d often implies the use of a nut (or a threaded counterpart) and typically passes through unthreaded parts.<\/li>\n\n\n\n<li>A \u201cscrew\u201d often goes into a part that either already has threads or is going to have them cut as the screw advances.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">The major identifiers: Diameter, Length (penetration depth) &amp; Pitch<\/h2>\n\n\n\n<p>Having cleared the bolt vs screw question, we should spend some time to understand the physical attributes that determine what a fastener is and how it functions.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Diameter (the thickness)<\/h3>\n\n\n\n<p>When you see a specification like \u201cM10\u201d or \u201c\u00bd inch\u201d, that is referring to the nominal diameter of the fastener &#8211; the major diameter of the thread (i.e., the outermost thread crest). For example, in metric you may see \u201cM10 \u00d7 1.5\u201d meaning a 10 mm diameter bolt. In imperial you might see \u201c\u00bd-13 UNC\u201d meaning half-inch diameter.<\/p>\n\n\n\n<p>Diameter matters because it affects:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The clearance or hole size required<\/li>\n\n\n\n<li>The strength of the fastener (larger diameter = more material = stronger or &#8220;higher tensile strength&#8221;)<\/li>\n\n\n\n<li>The compatibility with nuts or tapped holes<\/li>\n<\/ul>\n\n\n\n<p>Here\u2019s a nice diagram showing major diameter, pitch diameter, minor diameter:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"855\" height=\"553\" src=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/screw_thread.png\" alt=\"\" class=\"wp-image-99\" srcset=\"https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/screw_thread.png 855w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/screw_thread-300x194.png 300w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/screw_thread-768x497.png 768w, https:\/\/kyleward.ca\/wp-content\/uploads\/2025\/10\/screw_thread-417x270.png 417w\" sizes=\"auto, (max-width: 855px) 100vw, 855px\" \/><\/figure>\n\n\n\n<p> <a href=\"https:\/\/www.fastenerdata.co.uk\/screw-threads\">https:\/\/www.fastenerdata.co.uk\/screw-threads<\/a> &#8211; Link to this picture &#8211; great additional reading!<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Length \/ Penetration Depth<\/h3>\n\n\n\n<p>Length is how far the fastener will extend (or engage) in an assembly. But \u201clength\u201d can mean different things depending on the head style (did you measure from under the head or from the top?), and \u201cpenetration\u201d can refer to how deep the threaded part goes into material or how much shank vs. thread remains engaged.<\/p>\n\n\n\n<p>Here are some things to keep in mind:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>For a typical hex-head bolt (non-countersunk) you measure from the underside of the head to the tip of the bolt.<\/li>\n\n\n\n<li>For a countersunk head screw you measure from the top of the head because the head sits flush.<\/li>\n\n\n\n<li>If only part of a bolt is threaded, you may also care about how many threads are engaged and how long the un-threaded shank is (for shear vs tension loads).<\/li>\n\n\n\n<li>If the bolt is too short, you risk not engaging enough threads or not compressing the parts properly. Too long, and you might interfere with other components or cause clearance issues.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Thread Pitch<\/h3>\n\n\n\n<p>Finally we get to thread pitch and Threads Per Inch. Thread pitch is the distance between adjacent threads in metric systems (e.g., 1.25 mm). In imperial systems the comparable measure is \u201cthreads per inch\u201d (TPI) \u2014 e.g., 20 TPI means there are 20 threads in one inch of length. <br>This distinction is well explained in this video:<\/p>\n\n\n\n<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/BdRDTtHVN6I?si=AQjGuhwpVbtI3h5S\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n\n\n<p>Why pitch (or TPI) matters:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It determines how fast the fastener advances per turn (one turn on a coarse thread moves more than one turn on a fine thread).<\/li>\n\n\n\n<li>It affects clamp force, adjustment precision, and how the load is shared across threads.<\/li>\n\n\n\n<li>Using the wrong pitch (mixing metric and imperial, or coarse vs fine) can lead to damage of the threads, incorrect fit, or failure.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Let&#8217;s put it all together &#8211; some examples<\/h3>\n\n\n\n<p>Imagine you\u2019re specifying a fastener. In metric you might write:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><code><strong>M10 \u00d7 1.5 \u00d7 40<\/strong><br>Meaning: 10 mm major diameter, 1.5 mm thread pitch, 40 mm length.<\/code><\/p>\n<\/blockquote>\n\n\n\n<p>In imperial you might write:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><code><strong>\u00bd-13 UNC \u00d7 2\u00be\u2033<\/strong><br>Meaning: \u00bd-inch diameter, 13 threads-per-inch (UNC coarse series), length 2.75 inches.<\/code><\/p>\n<\/blockquote>\n\n\n\n<p>In real assemblies you\u2019ll also specify head style (hex, countersunk), thread length, material\/grade, finish etc. But getting diameter, length and pitch correct is the starting point.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to measure those three key things<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Tools you\u2019ll want<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Digital or dial calipers (for diameter, length)<\/li>\n\n\n\n<li>Thread pitch gauge (metric\/imperial) to match the threads and determine pitch or TPI. There&#8217;s a good <a href=\"https:\/\/en.wikipedia.org\/wiki\/Thread_pitch_gauge\" target=\"_blank\">Wikipedia article<\/a> on how to use these!<\/li>\n\n\n\n<li>Ruler or tape measure (for rough checks)<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step-by-step measurement process<\/h3>\n\n\n\n<p>Here\u2019s a walk-through of how you might measure a fastener:<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1. Measure the diameter<\/h4>\n\n\n\n<p>For a bolt that has a shank (smooth part between the threads and the head), place your caliper jaws across the diameter of the shank, for a bolt that has no shank place your caliper jaws across the outer thread crests (major diameter) of the threaded section. Record the reading in mm or inches depending on the type of bolt you have. For accuracy, take multiple readings at different positions (to check for taper or wear).<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. Determine the pitch or TPI<\/h4>\n\n\n\n<p>Use your thread pitch gauge:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In metric: match the gauge leaf to the threads until it fits snugly; read the marked pitch (e.g., 1.25 mm).<\/li>\n\n\n\n<li>In imperial: use a TPI gauge and corresponding leaf or count threads over an inch to determine how many threads exist per inch.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">3. Measure the length (penetration)<\/h4>\n\n\n\n<p>Decide what length you need: for a typical hex headed bolt you measure from the flat underside of the head to the tip of the threads. For a countersunk screw you measure from the top of the head (because the head sits flush) to the tip of the threads. Use your calipers to get that reading. <\/p>\n\n\n\n<p>If a video is more your thing, check out this detailed tutorial:<\/p>\n\n\n\n<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/14JX6lnCw4w?si=BxRd8Xpt4Ne8CI0n&amp;start=0&#038;end=403\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n\n\n<p>Now that you&#8217;ve got the skills to not only know what the difference between a metric and imperial fastener is and what diameter, penetration depth, and pitch is, but how to also measure those three key things give it a shot in this interactive animation seen below (click <a href=\"https:\/\/cdn2.cdxlearning.ca\/public_share\/FS\/FS_TPIass_01_C1\/FS_TPIass_01_C1.html\">here<\/a> to open it in a full screen window &#8211; it&#8217;s a bit easier to read). Record your answers as we&#8217;ll go through them in our sync session!<\/p>\n\n\n\n<iframe loading=\"lazy\" src=\"https:\/\/cdn2.cdxlearning.ca\/public_share\/FS\/FS_TPIass_01_C1\/FS_TPIass_01_C1.html\" width=\"600\" height=\"400\" frameborder=\"0\"><\/iframe>\n\n\n\n<h2 class=\"wp-block-heading\">Sources<\/h2>\n\n\n\n<p><br><a href=\"https:\/\/en.wikipedia.org\/wiki\/Bolt_%28fastener%29\">https:\/\/en.wikipedia.org\/wiki\/Bolt_%28fastener%29<\/a><br><a href=\"https:\/\/en.wikipedia.org\/wiki\/Screw\">https:\/\/en.wikipedia.org\/wiki\/Screw<\/a><br><a href=\"https:\/\/www.fastenerdata.co.uk\/screw-threads\">https:\/\/www.fastenerdata.co.uk\/screw-threads<\/a><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Threaded Fasteners This post is to support your learning before we meet synchronously to recap what you&#8217;ve discovered in regards to bolts and screws. Please take some time to read through, click on some linked resources, test your knowledge with the interactive animation, and if you&#8217;d like &#8211; try some of these new skills around your house! What exactly is a fastener &#8211; and why does it matter? Everyday objects, machines, furniture, vehicles\u2014the unseen force holding much of it together&#8230;<\/p>\n<p class=\"read-more\"><a class=\"btn btn-default\" href=\"https:\/\/kyleward.ca\/?page_id=92\"> Read More<span class=\"screen-reader-text\">  Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-92","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/pages\/92","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kyleward.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=92"}],"version-history":[{"count":10,"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/pages\/92\/revisions"}],"predecessor-version":[{"id":110,"href":"https:\/\/kyleward.ca\/index.php?rest_route=\/wp\/v2\/pages\/92\/revisions\/110"}],"wp:attachment":[{"href":"https:\/\/kyleward.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=92"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}