{"id":9200,"date":"2026-08-20T10:02:52","date_gmt":"2026-08-20T02:02:52","guid":{"rendered":"https:\/\/broachingmach.com\/?p=9200"},"modified":"2026-08-20T10:02:52","modified_gmt":"2026-08-20T02:02:52","slug":"broaching-vs-hobbing","status":"publish","type":"post","link":"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/","title":{"rendered":"Broaching vs Hobbing: Choosing the Right Gear and Spline Machining Process"},"content":{"rendered":"<figure class=\"wp-block-image\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1536\" height=\"1024\" src=\"https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech.png\" alt=\"Internal spline broaching versus external gear hobbing comparison\" class=\"wp-image-9182\" srcset=\"https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech.png 1536w, https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech-300x200.png 300w, https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech-1024x683.png 1024w, https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech-768x512.png 768w, https:\/\/broachingmach.com\/wp-content\/uploads\/2026\/08\/4-broaching-vs-hobbing-tech-18x12.png 18w\" sizes=\"(max-width: 1536px) 100vw, 1536px\" \/><\/figure>\n\n\n<p>Broaching and hobbing are two of the most widely used processes for cutting gear teeth and splines, yet they remove metal in fundamentally different ways and suit fundamentally different parts. Choosing between them is rarely a matter of which process is &#8220;better&#8221; \u2014 it comes down to where the teeth are, how many parts you need to make, and how often your designs change. This guide compares the two across capability, accuracy, tooling cost, and volume economics.<\/p><div id=\"ez-toc-container\" class=\"ez-toc-v2_0_86 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<div class=\"ez-toc-title\" style=\"cursor:inherit\">Indice dei contenuti<\/div>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Allinea la tabella dei contenuti\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewbox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewbox=\"0 0 24 24\" version=\"1.2\" baseprofile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Broaching_vs_Hobbing_at_a_Glance\" >Broaching vs. Hobbing at a Glance<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#How_Broaching_Works_Form_Cutting_One_Tooth_at_a_Time\" >How Broaching Works: Form Cutting, One Tooth at a Time<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#How_Hobbing_Works_Continuous_Generation_from_a_Worm-Shaped_Cutter\" >How Hobbing Works: Continuous Generation from a Worm-Shaped Cutter<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Internal_vs_External_Teeth_The_Decisive_Difference\" >Internal vs. External Teeth: The Decisive Difference<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Broaching_vs_Hobbing_Side-by-Side_Comparison\" >Broaching vs. Hobbing: Side-by-Side Comparison<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Accuracy_Bought_with_the_Tool_or_Built_into_the_Machine\" >Accuracy: Bought with the Tool or Built into the Machine?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Cost_Economics_Tooling_Changeover_and_Volume\" >Cost Economics: Tooling, Changeover, and Volume<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Where_Shaping_and_Power_Skiving_Fit_In\" >Where Shaping and Power Skiving Fit In<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Choosing_the_Right_Process_Four_Common_Scenarios\" >Choosing the Right Process: Four Common Scenarios<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#1_High-volume_internal_spline_gears_%E2%80%94_transmission_components\" >1. High-volume internal spline gears \u2014 transmission components<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#2_External_gears_small-to-medium_batches\" >2. External gears, small-to-medium batches<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#3_Internal_teeth_at_very_high_volume\" >3. Internal teeth at very high volume<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#4_Keyways_and_non-round_profiles\" >4. Keyways and non-round profiles<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Frequently_Asked_Questions\" >Frequently Asked Questions<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#What_are_the_disadvantages_of_broaching\" >What are the disadvantages of broaching?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#What_are_the_disadvantages_of_gear_hobbing\" >What are the disadvantages of gear hobbing?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#What_is_the_purpose_of_broaching\" >What is the purpose of broaching?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/broachingmach.com\/it\/broaching-vs-hobbing\/#Can_broaching_be_performed_on_a_CNC_mill\" >Can broaching be performed on a CNC mill?<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n\n\n\n\n<p>If you take away only one point before reading further, make it this: <strong>if the teeth are on the inside of the part, hobbing is not an option \u2014 broaching, shaping, or power skiving are your choices. If the teeth are on the outside, hobbing is usually the most flexible and productive route.<\/strong><\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Broaching_vs_Hobbing_at_a_Glance\"><\/span>Broaching vs. Hobbing at a Glance<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Broaching is a <strong>form-cutting process<\/strong>. A long, multi-toothed cutting tool \u2014 the broach \u2014 is pushed or pulled through (or across) the workpiece in a single linear pass. Each tooth on the broach stands slightly taller than the one before it, so each tooth strips away a thin slice of stock until the final finishing teeth imprint the exact profile of the finished part. The tool does all the work; the machine provides the straight motion and the force.<\/p>\n\n\n\n<p>Hobbing is a <strong>generating process<\/strong>. The hob is a worm-shaped cutter that rotates in tight coordination with the rotating workpiece, mimicking the mesh of a worm gear and a gear. As the two axes turn at a precise ratio, the hob&#8217;s cutting edges progressively envelope the tooth flanks, and a continuous feed motion carries the cutter across the full face width of the gear. No single cutting edge ever has the finished tooth profile \u2014 it is generated, stroke by stroke, from the coordinated rotation of cutter and part.<\/p>\n\n\n\n<ul>\n<li><strong>Internal splines, internal gears, keyways, non-round holes:<\/strong> broaching territory.<\/li>\n<li><strong>External spur and helical gears:<\/strong> hobbing territory.<\/li>\n<li><strong>High-volume, one-design parts:<\/strong> broaching wins on cost per part.<\/li>\n<li><strong>Multi-part-number, low-to-medium volume:<\/strong> hobbing wins on flexibility.<\/li>\n<\/ul>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"How_Broaching_Works_Form_Cutting_One_Tooth_at_a_Time\"><\/span>How Broaching Works: Form Cutting, One Tooth at a Time<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>A broach is best understood as a whole roughing and finishing operation compressed into a single tool. The front section \u2014 the roughing teeth \u2014 removes the bulk of the stock, with each tooth taking a small, controlled bite. The middle section \u2014 the semi-finishing teeth \u2014 brings the form close to final size with progressively smaller bites. The last few teeth are the finishing teeth: they carry the exact profile of the finished spline, keyway, or gear tooth and set the final dimensions and surface finish in the same pass. The small height difference between consecutive teeth is known as the rise per tooth, and it is the primary variable that balances cutting load against tool life and finish.<\/p>\n\n\n\n<p>Because the cutting load is distributed across many teeth, a broach removes a large amount of material in one pass without demanding extreme spindle power. On a vertical or horizontal broaching machine, the complete profile of an internal spline is produced in a single stroke \u2014 no multi-setup sequencing, no mid-cycle tool changes, and no reliance on machine kinematics, because the geometry lives in the tool itself. Our overview of <a href=\"https:\/\/broachingmach.com\/it\/what-is-broaching\/\">what broaching is and how it works<\/a> covers machine types and tool anatomy in more detail.<\/p>\n\n\n\n<p>The classic broaching applications are internal forms: keyways in bores, involute spline holes, internal gear teeth, and non-round profiles such as hexagons and squares. External broaching \u2014 on surface or pot-broaching machines \u2014 is also well established in high-volume automotive lines. For a deep dive into the most common application, see our <a href=\"https:\/\/broachingmach.com\/it\/spline-broaching-the-complete-guide\/\">complete guide to spline broaching<\/a>.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"How_Hobbing_Works_Continuous_Generation_from_a_Worm-Shaped_Cutter\"><\/span>How Hobbing Works: Continuous Generation from a Worm-Shaped Cutter<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>A hob is essentially a worm gear that has been gashed with flutes and relief-ground so that its threads become rows of cutting edges. When the hob is set at an angle to the workpiece so that its thread direction aligns with the tooth direction being cut, it meshes with the blank the way a worm meshes with a worm wheel. As the hob turns, the workpiece rotates in a fixed ratio to it \u2014 one hob revolution advances the work by the number of starts on the hob \u2014 so the process indexes continuously rather than tooth by tooth around the blank.<\/p>\n\n\n\n<p>While the coordinated rotation generates the tooth profile, an axial feed drives the hob along the gear&#8217;s face width, with tangential or radial feed strategies used to optimize the cutting pattern. Each tooth flank emerges as the envelope of many successive cutting edges. This is why one hob of a given module and pressure angle can cut gears of almost any tooth count \u2014 the profile is not built into the tool, it is generated by the mesh relationship. Spur gears, helical gears, worm wheels, and splines are all hobbed daily on CNC hobbing machines.<\/p>\n\n\n\n<p>The consequence of the generating principle is that accuracy depends on the whole kinematic chain: the machine&#8217;s synchronization, hob runout, the hob&#8217;s precision grade, wear, and thermal stability. Modern CNC hobbing machines with electronic gearboxes achieve excellent results, but the machine \u2014 not a single dedicated tool \u2014 carries the burden of precision.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Internal_vs_External_Teeth_The_Decisive_Difference\"><\/span>Internal vs. External Teeth: The Decisive Difference<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>This is the single most important technical distinction between the two processes, and it is non-negotiable: <strong>a hob cuts from the outside. The cutter must wrap around the outside diameter of the blank to generate teeth, and it physically cannot reach inside a bore.<\/strong> Internal gears and internal splines therefore cannot be hobbed \u2014 not expensively, not slowly, not at all. The geometry forbids it.<\/p>\n\n\n\n<p>When the teeth are on the inside, your realistic options are:<\/p>\n\n\n\n<ul>\n<li><strong>Brocciatura<\/strong> \u2014 the fastest and most consistent method for high-volume internal splines, internal gears, and keyways, producing the finished profile in one pass.<\/li>\n<li><strong>Shaping (slotting)<\/strong> \u2014 a generating process using a reciprocating pinion-type cutter. It can reach internal teeth and teeth close to shoulders, but it is slower than broaching.<\/li>\n<li><strong>Power skiving<\/strong> \u2014 a newer generating process in which a crossed-axis cutter and the workpiece rotate at high speed in synchrony. It is considerably faster than shaping for internal gears and delivers excellent surface finish, at the cost of demanding machine and tooling requirements. We compare the two directly in <a href=\"https:\/\/broachingmach.com\/it\/broaching-vs-power-skiving-internal-gears\/\">broaching vs. power skiving for internal gears<\/a>.<\/li>\n<\/ul>\n\n\n\n<p>When the teeth are on the outside, the picture flips. Hobbing is the default for external gears across virtually every industry, from fine-module transmission components to large industrial gear wheels. External splines can also be broached on surface or pot broaching machines, and on dedicated transfer-line equipment this is common \u2014 but it requires specialized machinery and a tool investment that only makes sense at serious volumes.<\/p>\n\n\n\n<p>So the first question in any process selection is not cost or cycle time. It is simply: <em>are the teeth internal or external?<\/em> Internal points you toward broaching (or its generating alternatives); external points you toward hobbing.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Broaching_vs_Hobbing_Side-by-Side_Comparison\"><\/span>Broaching vs. Hobbing: Side-by-Side Comparison<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<table>\n<thead>\n<tr>\n<th scope=\"col\">Dimensione<\/th>\n<th scope=\"col\">Brocciatura<\/th>\n<th scope=\"col\">Hobbing<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Internal teeth \/ splines<\/strong><\/td>\n<td>Core capability \u2014 internal splines, internal gears, keyways in one pass<\/td>\n<td>Not possible \u2014 geometric limitation; hobs cannot reach inside a bore<\/td>\n<\/tr>\n<tr>\n<td><strong>External teeth \/ splines<\/strong><\/td>\n<td>Possible on surface\/pot broaching machines; economical only at high volume<\/td>\n<td>Default process for external spur and helical gears and splines<\/td>\n<\/tr>\n<tr>\n<td><strong>Cycle time per part<\/strong><\/td>\n<td>Very fast \u2014 complete profile in a single stroke, minimal part handling<\/td>\n<td>Productive continuous cutting, but cycle grows with face width, depth, and number of passes<\/td>\n<\/tr>\n<tr>\n<td><strong>Achievable accuracy<\/strong><\/td>\n<td>Determined by the broach itself; highly repeatable part to part while the tool holds its edge<\/td>\n<td>Depends on machine kinematics, hob grade, setup, and thermal control; modern CNC hobs achieve high precision at increasing machine cost<\/td>\n<\/tr>\n<tr>\n<td><strong>Module \/ size range<\/strong><\/td>\n<td>Best suited to small and medium modules and part sizes bounded by machine tonnage and stroke length<\/td>\n<td>Very wide \u2014 from fine-module instrument gears to large heavy-industry gears<\/td>\n<\/tr>\n<tr>\n<td><strong>Tooling cost<\/strong><\/td>\n<td>High \u2014 each broach is engineered for one specific part number<\/td>\n<td>Moderate \u2014 hobs are semi-standard; one hob serves many tooth counts within a module<\/td>\n<\/tr>\n<tr>\n<td><strong>Design changes<\/strong><\/td>\n<td>Expensive \u2014 a profile change means a new broach<\/td>\n<td>Cheap \u2014 a parameter change plus, at most, a different hob<\/td>\n<\/tr>\n<tr>\n<td><strong>Changeover flexibility<\/strong><\/td>\n<td>Low \u2014 one tool, one part; changeover means swapping dedicated tooling<\/td>\n<td>High \u2014 quick changeovers across a family of gears with standard tooling<\/td>\n<\/tr>\n<tr>\n<td><strong>Machine investment<\/strong><\/td>\n<td>Dedicated broaching machine (vertical, horizontal, or rotary table)<\/td>\n<td>CNC gear hobbing machine<\/td>\n<\/tr>\n<tr>\n<td><strong>Volume economics<\/strong><\/td>\n<td>Tooling amortizes quickly; cost per part falls steeply with volume<\/td>\n<td>Balanced across volumes; strongest where part variety is high and batches are smaller<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n<p>Read down the table and a pattern appears: broaching trades flexibility for speed and repeatability, while hobbing trades single-part productivity for universality. Neither column is &#8220;better&#8221; \u2014 they are optimized for different factories and different order books.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Accuracy_Bought_with_the_Tool_or_Built_into_the_Machine\"><\/span>Accuracy: Bought with the Tool or Built into the Machine?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Broaching accuracy is, in a real sense, purchased in advance. Because broaching is a form process, the finished profile is a direct imprint of the broach&#8217;s finishing teeth: if the broach is ground to a high standard, every part coming off the machine inherits that standard, part after part, with minimal dependence on machine alignment. This is why broached internal splines are prized for consistency in high-volume components \u2014 the process has very few degrees of freedom in which error can creep in. The main accuracy risks are tool wear, re-sharpening quality, and the quality of the workpiece datum (the bore and face that locate the part).<\/p>\n\n\n\n<p>Hobbing accuracy is earned on the shop floor. The tooth profile is generated by the synchronized rotation of the hob and the workpiece, so the error budget includes the machine&#8217;s transmission accuracy, the electronic gearbox, hob runout and mounting, hob class, wear on the cutting edges, backlash in the workpiece drive, and thermal drift during long runs. Modern CNC hobbing machines manage these factors well and can produce high-precision gears reliably \u2014 but precision-class machines command a premium, and holding tight tolerances demands disciplined setup and maintenance practices.<\/p>\n\n\n\n<p>For practical sourcing decisions: an internal spline or internal gear with a tight tolerance and stable volume is best served by broaching, which delivers that tolerance with less process variability than any generating alternative. For external gears, hobbing offers a wide choice of machine classes, and you simply select the precision tier that matches the drawing.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Cost_Economics_Tooling_Changeover_and_Volume\"><\/span>Cost Economics: Tooling, Changeover, and Volume<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>The economic comparison hinges on one word: <strong>dedication<\/strong>. A broach is engineered and ground for exactly one part number \u2014 its profile, tooth counts, depth-of-cut progression, and finishing allowance all live in the tool. That makes the tool expensive and its lead time real, but once the tool exists, each additional part costs very little in process time and effort. A well-maintained broach machines thousands of parts over its life and can be re-sharpened and re-coated to extend that further. The higher the volume, the more the tooling investment amortizes \u2014 which is why broaching dominates mass production of internal splined components.<\/p>\n\n\n\n<p>A hob, by contrast, is a semi-standard product. Specify the module, pressure angle, and profile type, and the same hob will cut nearly any tooth count in that family. Combined with quick fixture changes and CNC programs, a single hobbing machine can flow through dozens of part numbers in a week. You give up the single-stroke speed of broaching, but you avoid betting the tooling budget on any single design: when a customer changes a tooth count, the hobbing shop absorbs it as a setup change; the broaching shop absorbs it as a new tool purchase.<\/p>\n\n\n\n<p>The crossover logic follows directly:<\/p>\n\n\n\n<ul>\n<li><strong>High volume, stable design, internal features<\/strong> \u2014 broaching&#8217;s cost per part is difficult to beat with anything else.<\/li>\n<li><strong>High volume, stable design, external features<\/strong> \u2014 both processes can compete; dedicated broaching lines win at extreme volumes, hobbing wins in the middle.<\/li>\n<li><strong>Low-to-medium volume or frequent design changes<\/strong> \u2014 hobbing&#8217;s flexibility avoids stranded tooling investment.<\/li>\n<li><strong>Internal features, but volumes too small to justify a broach<\/strong> \u2014 shaping or power skiving becomes worth evaluating.<\/li>\n<\/ul>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Where_Shaping_and_Power_Skiving_Fit_In\"><\/span>Where Shaping and Power Skiving Fit In<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Any honest comparison of broaching and hobbing should acknowledge the other two processes that complete the picture. <strong>Gear shaping<\/strong> uses a pinion-shaped cutter that reciprocates while rolling in mesh with the workpiece. It is the most versatile process of the family: it reaches internal teeth, cuts external teeth tight against shoulders where a hob cannot withdraw, and handles forms that defeat other processes \u2014 at the price of being the slowest of the family. <strong>Power skiving<\/strong> is the modern challenger: by rotating a crossed-axis tool and the workpiece at high synchronized speeds, it generates internal teeth far faster than shaping with excellent surface finish, and it is increasingly specified in dry-cutting production environments.<\/p>\n\n\n\n<p>The shorthand version: broaching buys speed and repeatability with tooling dedication; hobbing buys external-gear flexibility with machine sophistication; shaping buys universality with time; skiving buys a middle path between shaping&#8217;s flexibility and broaching&#8217;s speed, demanding high-rigidity machinery and precision tooling in return. For internal gears specifically, the decision increasingly comes down to <a href=\"https:\/\/broachingmach.com\/it\/broaching-vs-power-skiving-internal-gears\/\">broaching versus power skiving<\/a>, which we treat in a dedicated comparison.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Choosing_the_Right_Process_Four_Common_Scenarios\"><\/span>Choosing the Right Process: Four Common Scenarios<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"1_High-volume_internal_spline_gears_%E2%80%94_transmission_components\"><\/span>1. High-volume internal spline gears \u2014 transmission components<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Geared components with internal splines \u2014 transmission gears being the classic example \u2014 are the textbook broaching application. The teeth cannot be hobbed, volumes are high, designs are stable for the life of the program, and part-to-part consistency is critical. A broaching machine at the end of the soft-machining line cuts the finished spline bore in one pass, hour after hour. Our guide to <a href=\"https:\/\/broachingmach.com\/it\/transmission-gear-internal-spline-broaching\/\">transmission gear internal spline broaching<\/a> shows how these cells are configured.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"2_External_gears_small-to-medium_batches\"><\/span>2. External gears, small-to-medium batches<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Job shops and tier suppliers running many part numbers against moderate demand should default to hobbing. One CNC hobbing machine, a tool crib of standard hobs, and a set of fixtures cover an enormous range of external gears, with no per-part tooling investment and therefore no minimum viable quantity.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"3_Internal_teeth_at_very_high_volume\"><\/span>3. Internal teeth at very high volume<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>When annual volumes are large and the internal profile is fixed \u2014 internal ring gears, spline housings, constant-mesh components \u2014 broaching has no real competitor on cost per part. Shaping and skiving compete on flexibility and finish; broaching competes on throughput and unit economics, and at scale it usually wins both.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"4_Keyways_and_non-round_profiles\"><\/span>4. Keyways and non-round profiles<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Not every broaching decision is about gears. Keyways in bores, hexagonal and square profiles, and other internal forms are broached because the process produces them accurately in one pass. For lower volumes or one-offs, these features can also be milled \u2014 see <a href=\"https:\/\/broachingmach.com\/it\/broaching-vs-milling-internal-keyways-profiles\/\">broaching vs. milling for internal keyways and profiles<\/a>.<\/p>\n\n\n\n<h2><span class=\"ez-toc-section\" id=\"Frequently_Asked_Questions\"><\/span>Frequently Asked Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"What_are_the_disadvantages_of_broaching\"><\/span>What are the disadvantages of broaching?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>The main drawbacks are tooling-related. Broaches are expensive, dedicated tools \u2014 each one is built for a single part geometry, so a design change requires a new broach, and a shop running many part numbers needs a matching tool inventory. Lead times for new broaches are measured in weeks. There are also geometric limits: a conventional internal broach must pass completely through the workpiece, so blind bores need enough relief at the bottom for tool runout, and part sizes are bounded by machine stroke length and tonnage.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"What_are_the_disadvantages_of_gear_hobbing\"><\/span>What are the disadvantages of gear hobbing?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>The hard limitation is that hobbing only cuts external teeth \u2014 internal gears and splines are outside its reach. Beyond that: the hob needs clearance to withdraw, so gears with teeth close to shoulders or flanges (double-reduction clusters, for example) may need shaping instead. Accuracy depends on the machine&#8217;s kinematic chain, so tight tolerances require a precision-class machine and disciplined setup. And changeovers involve hob swaps, fixture changes, and synchronization setup, which makes hobbing less attractive than broaching for very high volumes of a single part.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"What_is_the_purpose_of_broaching\"><\/span>What is the purpose of broaching?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>The purpose of broaching is to produce internal profiles \u2014 keyways, involute splines, internal gear teeth, and non-round holes like hexes and squares \u2014 accurately and extremely efficiently. Because the roughing, semi-finishing, and finishing stages are built into one tool, a broaching machine delivers a finished, repeatable profile in a single pass, which is exactly what high-volume production of splined and geared components demands.<\/p>\n\n\n\n<h3><span class=\"ez-toc-section\" id=\"Can_broaching_be_performed_on_a_CNC_mill\"><\/span>Can broaching be performed on a CNC mill?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Conventional broaching cannot \u2014 it needs the long, powerful linear stroke of a broaching machine, which machining centers are not built to provide. However, <strong>rotary broaching<\/strong> is a related technique that does run on CNC mills and lathes: a spinning broach is pressed into the workpiece at a slight tilt, wobbling its cutting edges into the material to form small hexagonal, square, or serrated forms. It is a niche complement rather than a substitute, suited to small forms rather than precision spline bores. We cover the trade-offs in <a href=\"https:\/\/broachingmach.com\/it\/broaching-vs-milling-internal-keyways-profiles\/\">broaching vs. milling for internal features<\/a>.<\/p>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p><strong>Broaching vs. hobbing, in one sentence: hobbing is the flexible workhorse for external gears; broaching is the high-volume specialist that owns everything inside the bore.<\/strong><\/p>\n\n\n\n<p>If your production involves internal splines or internal gear teeth at serious volumes, we build broaching machines and engineer the broaches that go with them \u2014 as a turnkey package, sized to your parts and your output targets. Explore our <a href=\"https:\/\/broachingmach.com\/it\/broaching-machines\/\">broaching machines<\/a> or send us your part drawings and annual volumes, and we will recommend the machine-tonnage and tooling configuration that fits.<\/p>","protected":false},"excerpt":{"rendered":"<p>Broaching vs hobbing: how each process cuts gears and splines, internal vs external teeth, accuracy, tooling cost, and when to choose one for production.<\/p>","protected":false},"author":1,"featured_media":9181,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[23],"tags":[],"class_list":["post-9200","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-broaching"],"_links":{"self":[{"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/posts\/9200","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/comments?post=9200"}],"version-history":[{"count":1,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/posts\/9200\/revisions"}],"predecessor-version":[{"id":9201,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/posts\/9200\/revisions\/9201"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/media\/9181"}],"wp:attachment":[{"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/media?parent=9200"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/categories?post=9200"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/broachingmach.com\/it\/wp-json\/wp\/v2\/tags?post=9200"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}