{"id":3574,"date":"2026-10-09T07:23:23","date_gmt":"2026-10-08T23:23:23","guid":{"rendered":"http:\/\/www.zaashco.com\/blog\/?p=3574"},"modified":"2026-10-09T07:23:23","modified_gmt":"2026-10-08T23:23:23","slug":"are-0-carriage-bolts-available-in-different-head-thicknesses-422c-be04b6","status":"publish","type":"post","link":"http:\/\/www.zaashco.com\/blog\/2026\/10\/09\/are-0-carriage-bolts-available-in-different-head-thicknesses-422c-be04b6\/","title":{"rendered":"Are 0 Carriage Bolts available in different head thicknesses?"},"content":{"rendered":"

Hey there, fellow builders, fabricators, and random folks who\u2019ve spent way too long staring at fastener specs (I see you). If you\u2019ve ever picked up a 0 carriage bolt\u2014you know, the kind with that classic round, smooth head and square shank under it that locks into wood or metal to keep it from spinning\u2014you\u2019ve probably had one question bug you at some point. I get it, because I\u2019m the guy on the other end of the phone when that question hits. I run a small, no-BS carriage bolt supply shop, so I field this exact query at least three times a week: Are 0 carriage bolts available in different head thicknesses? 0Carriage Bolts<\/a><\/p>\n

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First off, let\u2019s cut through the jargon, because \u201c0 carriage bolt\u201d doesn\u2019t mean it\u2019s a tiny, bolt-sized version of a carriage bolt\u2014though yeah, sometimes folks mix that up (shoutout to the customer last week who asked if we had 0-size bolts for a toy train. No, but I get the confusion). The \u201c0\u201d here is the ANSI (American National Standards Institute) standard number for the shank diameter: 0.5-inch, right? Wait, no\u2014wait, let\u2019s clarify that quick, because specs are where most headaches happen. ANSI B18.5 is the go-to for carriage bolts, and the size number (the 0 in 0 carriage bolt) actually corresponds to the shank\u2019s nominal diameter in sixteenths of an inch. So size 0 is 0\/16 = 0.5-inch shank. That\u2019s the standard baseline 0 carriage bolt you\u2019ll see on deck railings, fence posts, heavy-duty furniture frames\u2014stuff that needs to hold solid, not just hang together.<\/p>\n

Now, back to the head thickness question. This is way more important than it sounds, by the way. I once had a guy drive 45 minutes to my shop screaming about how his new deck boards split when he tightened his 0 carriage bolts. Turns out he grabbed the first box he found from the big box store, which had thinner heads, and when he cranked the wrench down, the head compressed the soft cedar and split the wood. If he\u2019d had a thicker head, that spread of load would\u2019ve saved him a whole afternoon of repairs and a new 2×6. So yeah, head thickness isn\u2019t a trivial spec\u2014it\u2019s a make-or-break for how well a bolt works.<\/p>\n

So, do we (as in, real 0 carriage bolt suppliers, not the big box chains that cut corners) make these with different head thicknesses? Hell yeah, and we\u2019ve been doing it for years\u2014though most people don\u2019t realize that, because standard specs only list one \u201cnominal\u201d thickness, not the variations that exist for specific use cases. Let\u2019s break this down, because there are three main categories of 0 carriage bolt head thickness, and none of them are one-size-fits-all.<\/p>\n

First, the standard nominal head thickness, per ANSI B18.5. That\u2019s the baseline for general use. For a size 0 (0.5-inch shank) carriage bolt, ANSI lists the round head thickness as 0.312 inches\u2014about 5\/16 of an inch. That\u2019s what you get in the generic boxes at hardware stores, and it works for most casual stuff: like attaching a picket to a fence rail, or hanging a small shelf that holds your toolbox. But here\u2019s the thing: ANSI\u2019s nominal spec is a minimum, right? Wait, no\u2014wait, let me double-check that, because I don\u2019t want to mislead anyone. No, actually, ANSI B18.5 specifies a minimum and maximum for head thickness, not just a single number. For size 0 carriage bolts, the head thickness ranges from 0.290 inches (min) to 0.330 inches (max). Oh, so that\u2019s a range, but is that the \u201cdifferent thicknesses\u201d people are asking about? Kind of, but most of the time when someone emails or calls asking for different head thicknesses, they\u2019re not talking about 0.04 inches of variation in the ANSI range. They\u2019re talking about thicker heads, or thinner heads, that aren\u2019t just within the standard spec.<\/p>\n

Which brings me to the second category: heavy-duty extra thick heads. These are the ones for when you\u2019re dealing with higher loads. Think structural work, like attaching a ledger board to your house (the part that holds your deck to the wall\u2014super important, don\u2019t skimp here) or mounting a heavy metal gate that weighs 200+ pounds. For these uses, a thinner standard head will flex or pull through the material over time. So we make size 0 carriage bolts with heads that are 0.375 inches thick\u20143\/8 of an inch. That\u2019s 20% thicker than the ANSI nominal max. The extra thickness means the load is spread over a bigger area, so it doesn\u2019t dig into wood or bend under tension. I had a commercial framer come in last month\u2014he was working on a small public park pavilion\u2014and he needed these thick heads because the deck posts were going to hold picnic tables and playground equipment. He told me a big box supplier sold him regular 0 bolts that bent halfway through the job, so he came to me for the thicker ones. I\u2019ve also got a buddy who builds horse barns\u2014he swears by the thick head 0 carriage bolts for attaching stall doors, because a spooked horse can slam a door hard enough to shear a thin-head bolt. That\u2019s not a story I take lightly.<\/p>\n

Then there\u2019s the third category: thin profile heads. Wait, who needs a thinner carriage bolt head, right? I thought that too, until a customer brought me a photo of his new backyard gate. He\u2019d used standard 0 carriage bolts, but the gate frame had a recessed notch for the bolt head, and the standard 0.312-inch head was too tall\u2014so when he closed the gate, it wouldn\u2019t latch. Turns out, thin heads are super useful for flush-mount applications where you don\u2019t want the bolt head sticking out or catching on things. For size 0 carriage bolts, we make thin heads that are 0.250 inches thick\u20141\/4 of an inch. That\u2019s almost a full 0.06 inches thinner than the minimum ANSI spec. The catch here is that you can\u2019t use these for high-load stuff, obviously\u2014they\u2019re for light to medium use, like the gate latch, or attaching a decorative trim to a bookshelf, or any project where clearance is tight. I actually keep a small bin of these thin heads in my shop for exactly that scenario, because I can\u2019t tell you how many times a customer has come in panicking because their custom woodworking project has a hidden groove that standard heads don\u2019t fit.<\/p>\n

Now, let\u2019s talk about why you don\u2019t hear about this stuff at your local big box store. It\u2019s simple: they stock the lowest common denominator\u2014standard thickness, lowest cost, and they move enough of them that they don\u2019t need to carry variations. We\u2019re a small supplier, so we cater to the people who actually need specifics. But wait, is there a catch to getting different head thicknesses for 0 carriage bolts? Yeah, sort of. First, availability. The thin and extra thick heads aren\u2019t sitting on a shelf next to the generic 0 bolts\u2014we don\u2019t mass produce them, because not everyone needs them. So you\u2019ve got to order them in advance, usually with a small lead time, unless we have leftover stock from a recent job. Second, material. Wait, some people ask if the thickness is different because of the material\u2014like, can you get stainless steel 0 carriage bolts with different head thicknesses? Absolutely. Same with hot-dip galvanized, plain carbon steel, even silicon bronze for outdoor marine projects. The thickness spec is separate from the material spec, so you can mix and match. Just make sure you specify both when you order: size 0, material, and head thickness, so you don\u2019t end up with the wrong thing.<\/p>\n

Wait, let\u2019s address a common myth here. Some folks think that \u201cdifferent head thicknesses\u201d just means a longer or shorter bolt, but no\u2014carriage bolts have a fixed shank length for each diameter, right? So a size 0 carriage bolt is available in lengths from, like, 1 inch up to 12 inches, but the head stays the same diameter (usually 0.75 inches for size 0) and the thickness is the variable. That\u2019s another thing I see people mix up: they\u2019ll say \u201cI need a thicker bolt\u201d and they mean longer, but no\u2014thickness is the height of the round head, not how long the shank is. Important distinction.<\/p>\n

I should also mention that not all suppliers do this. A lot of the big bolt distributors only carry the standard nominal thickness for size 0 carriage bolts, because it\u2019s cheaper to stock one SKU instead of three. That\u2019s why I started offering the variations\u2014after that deck repair customer a few years back, I realized most builders don\u2019t know that head thickness is a variable, not a fixed spec. I started carrying the extra thick heads first, then added the thin ones after that gate customer story. Now it\u2019s one of our most popular custom requests.<\/p>\n

Another thing: testing. How do we make sure the extra thick heads are actually strong enough? We send samples to a local materials lab to test shear and tensile strength, because we don\u2019t want to sell something that will fail. The thin heads, obviously, aren\u2019t rated for heavy loads, but we test those too just to make sure they don\u2019t snap when you tighten a wrench. We use the same high-quality steel for all our 0 carriage bolts\u2014no cheap, brittle steel that bends or snaps the second you look at it.<\/p>\n

Let me wrap this up with a real example to drive the point home. Last spring, I had a customer who was building a custom birdhouse? No, wait, a tiny cabin for his kids in the backyard\u2014like, 10×12, with a cedar floor and pine walls. He used standard 0 carriage bolts for the floor joists, but when he tightened the last one, the head pulled through the soft cedar. He came to me at 6pm on a Friday, panicking, because he had to get the cabin done for his kid\u2019s birthday party the next day. I had a bin of extra thick head 0 carriage bolts in stock, so he ran them to his place, replaced the bad bolts, and got the cabin finished just in time. He left me a $20 tip and a bag of homemade chocolate chip cookies. That\u2019s the stuff that makes this job worth it\u2014when you don\u2019t just sell a bolt, you solve a problem.<\/p>\n

So to circle back to the original question: Are 0 carriage bolts available in different head thicknesses? The short answer is hell yes, but most people don\u2019t know that because they\u2019re only buying generic bolts from big stores. The long answer is that there are three main thicknesses: standard nominal (for general use), extra thick (for high-load structural or heavy hardware jobs), and thin profile (for tight clearance or flush-mount projects). You just need to work with a supplier that actually carries these variations, not just the one-size-fits-all garbage.<\/p>\n

If you\u2019re working on a project right now and you\u2019re not sure which head thickness you need\u2014whether it\u2019s a deck, fence, gate, custom furniture, whatever\u2014hit me up. I can walk you through it, no pressure. I\u2019ve spent enough time around bolts to know exactly what works for what, and I won\u2019t sell you something you don\u2019t need. Just reach out to connect, and we can chat through your specs. No high-pressure sales, no confusing jargon, just straight answers about carriage bolts.<\/p>\n

<\/p>\n

Wait, one last thing: if you\u2019re ordering, make sure you\u2019re not mixing up shank size. Sometimes folks call a 0 carriage bolt a \u201c1\/2-inch bolt\u201d because that\u2019s the shank diameter, which is correct, but I always remind people to confirm the length too\u2014because a 1-inch bolt is way different than a 6-inch bolt. And if you have a super specific project, just send me the details, and I\u2019ll tell you if we have exactly what you need, or if we can get it in for you.<\/p>\n

Hex Bolts<\/a> References:<\/p>\n

    \n
  1. American National Standards Institute (ANSI). B18.5-2021: Fasteners, Bolts, Carriage, Square and Hex Heads (Regular, Short, and Long lengths), and Carriage Bolt and Nut Assembly. ANSI, 2021.<\/li>\n
  2. Fabricators & Manufacturers Association International. Fastener Selection Guide for Structural and General Fabrication Projects. FMA, 2022.<\/li>\n
  3. ASTM International. Standard Specification for Steel Carriage Bolts, 150 ksi Minimum Tensile Strength. ASTM A307\/A307M-21, 2021.<\/li>\n<\/ol>\n
    \n

    Ningbo Taida Fastener Manufacture Co., Ltd.<\/a>
    Ningbo Taida Fastener Manufacture Co., Ltd. is well-known as one of the leading 0carriage bolts manufacturers and suppliers in China. Please feel free to buy high quality 0carriage bolts at competitive price from our factory. Good service and punctual delivery are available.
    Address: No.286 Galaxy Road, Chengdong Industrial Park, Xiangshan Economic Development Zone, Ningbo China
    E-mail: suki@tdfasteners.com
    WebSite:     https:\/\/www.td-fasteners.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey there, fellow builders, fabricators, and random folks who\u2019ve spent way too long staring at fastener … Are 0 Carriage Bolts available in different head thicknesses?<\/span>Read more<\/a><\/p>\n","protected":false},"author":364,"featured_media":3574,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3537],"class_list":["post-3574","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-0carriage-bolts-4f95-be4039"],"_links":{"self":[{"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/posts\/3574","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/users\/364"}],"replies":[{"embeddable":true,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/comments?post=3574"}],"version-history":[{"count":0,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/posts\/3574\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/posts\/3574"}],"wp:attachment":[{"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/media?parent=3574"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/categories?post=3574"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.zaashco.com\/blog\/wp-json\/wp\/v2\/tags?post=3574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}