{"id":3473,"date":"2026-09-29T00:27:24","date_gmt":"2026-09-28T16:27:24","guid":{"rendered":"http:\/\/www.processfolks.com\/blog\/?p=3473"},"modified":"2026-09-29T00:27:24","modified_gmt":"2026-09-28T16:27:24","slug":"can-threading-tools-be-used-for-both-internal-and-external-threading-47f6-c93606","status":"publish","type":"post","link":"http:\/\/www.processfolks.com\/blog\/2026\/09\/29\/can-threading-tools-be-used-for-both-internal-and-external-threading-47f6-c93606\/","title":{"rendered":"Can threading tools be used for both internal and external threading?"},"content":{"rendered":"

Hey there, let\u2019s cut to the chase \u2013 if you\u2019re in manufacturing, construction, automotive, or literally any industry that uses fasteners, you\u2019ve probably stared at a threading tool and wondered: can this thing actually do both internal and external threading? I get it, because I run a threading tools supply business, and I field this exact question at least twice a week, usually over coffee with a shop foreman who\u2019s sick of renting two separate tool sets that take up half their tool chest (and their budget). Threading Tools<\/a><\/p>\n

<\/p>\n

Before I dive in, let\u2019s get one thing straight right up front \u2013 no, not every threading tool can pull off both internal and external work. But there are specific, purpose-built tools that absolutely can, and using them isn\u2019t just a \u201cnice-to-have\u201d \u2013 it\u2019s a game-changer for small shops, mid-sized operations, and even big-name OEMs looking to cut down on tooling costs, storage, and downtime. Let\u2019s break this down like we\u2019re chatting in a workshop, not a stuffy engineering seminar.<\/p>\n

First off, let\u2019s define what we\u2019re even talking about, because terminology gets messy fast. External threading is the stuff you see on a bolt, the outside of a pipe, or the end of a metal rod \u2013 you know, the threads that screw into a nut or another component. Internal threading is the opposite: the threads inside a hole, like the ones in a nut, a pipe fitting, or the threaded port on a hydraulic part. If you\u2019ve ever tried to thread a \u00bc\u201d-20 bolt into a nut, you did one external, one internal.<\/p>\n

Now, the old-school tools: if you\u2019ve ever used a set of hand taps (for internal) and dies (for external), those are separate, right? A tap\u2019s a pointy, fluted thing you twist into a hole, a die\u2019s a circular, notched plate you clamp around a rod. For decades, that\u2019s how shops did it \u2013 buy a tap set, a die set, separate tools, two times the cost, twice the storage. But over the last 15 years or so, tool manufacturers (myself included, since I\u2019m on the supply end) started realizing there\u2019s a gap here. Shops were wasting cash on duplicate tools they only used for one job. So they designed hybrid threading tools that can handle both.<\/p>\n

Wait, but how does that even work? Let\u2019s get into the nitty-gritty without boring you with CAD jargon. Take indexable threading inserts, for example \u2013 these are the popular inserts you see on CNC lathes and Swiss-type machines, the ones you swap out when they wear instead of throwing away the whole tool. A lot of people think those inserts are either for internal or external, but no \u2013 modern multi-purpose inserts are shaped to cut both. The nose angle and pitch are calibrated so one edge will cut external threads on a OD (outer diameter) and the opposite edge will cut internal threads on a ID (inner diameter) of the same pitch. I\u2019ve got a customer in a small agricultural parts shop that uses these inserts for tractor bolt holes and the rods that hold the plow blade \u2013 one insert does both, so they don\u2019t have to stock 10 different inserts for every thread size they use. That\u2019s $300 a month saved on tooling, by the way, not to mention less time hunting for the right insert between jobs.<\/p>\n

Another big one: adjustable threading tools, specifically for hand threading or small CNC work. I\u2019m talking about things like split die-rethreaders that have interchangeable heads, or even handheld tap-and-die combo tools that use the same handle for both a tap and a die. Wait, but I know what some of you are thinking \u2013 those cheap combo sets at the hardware store that break after two uses? Yeah, those are garbage, and I won\u2019t sell you anything like that. The professional-grade versions, though \u2013 the ones we supply to industrial shops \u2013 are made from high-speed steel (HSS) or solid carbide, precision-machined so there\u2019s no wobble, and they actually hold their thread form even after 50+ cuts. I had a guy call me last month panicking because his hardware store combo set broke mid-job on a custom bicycle frame, so I sent him a professional grade adjustable set that he\u2019s used for over 6 months now, doing both internal and external threads on titanium and aluminum. He sent me a text last week saying he hasn\u2019t touched his old separate tap and die set since. That\u2019s real, that\u2019s not a sales pitch fluff.<\/p>\n

But here\u2019s the catch \u2013 and this is the part most tool suppliers won\u2019t tell you, because they just want to sell you something \u2013 you can\u2019t use just any threading tool for both, and you can\u2019t push them beyond their limits. Let\u2019s talk about when it works, and when it doesn\u2019t.<\/p>\n

First, when multi-purpose threading tools shine: short run jobs, low to medium volume work, shops with limited tool storage, custom fabrication, and hobbyist or small business use. Let\u2019s say you\u2019re a HVAC tech that does custom ductwork, or a woodworker who makes custom furniture with threaded inserts for table legs. You need external threads on threaded rod and internal threads in the wood inserts \u2013 one tool, done. No need to haul around a toolbox full of taps and dies for every job. I supply a lot of HVAC guys with these combo sets, and they swear by them because they can fix a leaky pipe on a jobsite in 10 minutes without grabbing two separate tools from their truck storage.<\/p>\n

Now, when you should stick to separate tools: high-volume production, tight tolerance applications, exotic materials (like Inconel or ceramics), and large diameter threads (anything over 4 inches or so). Wait, why? Let\u2019s break it down. For high volume, indexable inserts designed specifically for internal threading will hold tighter tolerances over thousands of cuts than a multi-purpose insert, because they\u2019re optimized for one job. Exotic materials wear tools way faster, and a dedicated threading tool is engineered to handle the heat and friction of cutting those hard metals without skipping a thread. And large diameter threads? The tool needs more surface area to cut clean, and multi-purpose tools just don\u2019t have the rigidity for that \u2013 you\u2019ll get wobbly threads that strip or don\u2019t fit right. I had a customer in oil and gas try to use a multi-purpose insert on a 5-inch external pipe thread a while back, and he ended up wasting 3 feet of pipe because the thread was off by 0.002 inches \u2013 that\u2019s a big no-no for them, so they switched back to dedicated tools for all pipe work.<\/p>\n

Also, let\u2019s not forget about CNC threading vs. manual threading, because that changes the game too. On a CNC lathe, multi-purpose indexable inserts work great because the machine is precise, it controls the feed rate, so there\u2019s no human error messing up the thread form. Manual threading, though \u2013 you have to be more careful. If you\u2019re hand-threading a \u00bc\u201d-20 external thread with a combo die, you have to make sure you\u2019re applying even pressure, and backing off every half turn to clear chips, just like you would with a dedicated die. For hand-held internal threading with a combo tap, same thing \u2013 slow and steady, don\u2019t force it, or you\u2019ll strip the hole. I always tell new users of these tools to practice on scrap metal first, just to get the feel of it, before jumping into a critical part.<\/p>\n

Wait, another area people don\u2019t talk about: threading tools for injection molding and 3D printing? Yeah, those too. I supply a lot of prototype shops that use 3D printed molds, and they need to thread the mold cores and cavities \u2013 one tool that can do both saves them from buying separate tools for every mold insert. And since prototyping is usually low volume, multi-purpose tools are perfect here. I had a customer that makes medical device prototypes, and they use a small carbide combo tool to thread plastic mold parts \u2013 it\u2019s cheap, it works, and they don\u2019t have to stock a dozen taps and dies for their small prototype runs.<\/p>\n

Now, let\u2019s get to the part you\u2019re probably wondering: is using a threading tool for both internal and external actually worth the cost? Let\u2019s do the math, real quick, no fancy spreadsheets. If you\u2019re a small shop that uses 5 different thread sizes, buying separate taps and dies for each size would run you about $150-$200 per size, so $750-$1000 total. A professional multi-purpose set for those same 5 sizes runs about $300-$400 \u2013 that\u2019s 60% less upfront cost. Plus, less storage, less time spent switching tools between jobs, less downtime hunting for the right tap or die. For a mid-sized shop, that adds up to thousands of dollars a year in savings. I\u2019ve had customers tell me they\u2019ve saved over $10k a year on tooling after switching to multi-purpose threading tools, and that\u2019s money they can put back into hiring more staff or upgrading their equipment.<\/p>\n

But here\u2019s the thing, and I want to be totally transparent \u2013 not all multi-purpose threading tools are created equal. When I sell these, I make sure customers know to look for three things: material (carbide or premium HSS, not the cheap soft steel that bends), tolerance (the tool should be precision-ground to ANSI or ISO standards, not cast), and the number of cutting edges \u2013 more edges mean longer tool life. If a tool has only one edge for both internal and external, it\u2019s going to wear out faster, so look for ones with separate, hardened edges for each application. I\u2019ve seen cheap combo tools that use the same cutting edge for both, and they leave a rough, inconsistent thread that doesn\u2019t fit right. That\u2019s why I only stock tools from manufacturers that test every multi-purpose tool for both internal and external thread tolerance before they hit the shelves.<\/p>\n

Let me share a horror story, because this is real. A few years back, I had a customer buy a super cheap combo tool from a big-box hardware store for a job building custom gates. He was threading \u00bd\u201d-13 bolts and the matching nuts, and the tool left external threads that were slightly too big, and internal threads that were slightly too small. When he tried to screw them together, they stripped before they were even halfway. He called me upset, and I sent him a professional grade multi-purpose tool that did the job on the first try. He ended up going back and replacing all the bad bolts he made with the cheap tool, costing him an extra $800 in parts and lost time. That\u2019s why I\u2019m so upfront about the difference between cheap junk and professional multi-purpose tools \u2013 you get what you pay for.<\/p>\n

Now, should you invest in multi-purpose threading tools? Only if they fit your workflow. If you\u2019re a high-volume automotive plant running 24\/7 on a single thread size, a dedicated internal or external tool is going to be more efficient. But if you\u2019re a small shop, a fabricator, a repair tech, or a prototype shop, they\u2019re a no-brainer. They cut costs, save space, reduce downtime, and they\u2019re actually really easy to use once you get the hang of them.<\/p>\n

Wait, let\u2019s wrap this up with a quick recap so you don\u2019t have to scroll back through this whole thing:<\/p>\n

    \n
  1. Yes, certain purpose-built threading tools can handle both internal and external threading \u2013 just not every tool.<\/li>\n
  2. Multi-purpose indexable inserts (for CNC) and professional combo tap\/die sets (for manual work) are the main players here.<\/li>\n
  3. They work best for low\/medium volume, short runs, custom work, and small to mid-sized operations.<\/li>\n
  4. Stick to dedicated tools if you\u2019re doing high volume, tight tolerances, exotic materials, or large diameter threads.<\/li>\n
  5. Buy quality \u2013 cheap combo tools will cost you more in the long run.<\/li>\n<\/ol>\n

    At the end of the day, I started this business because I hated seeing small shops get ripped off by overpriced, one-use tools that fill up tool chests and eat into profits. Multi-purpose threading tools aren\u2019t a gimmick \u2013 they\u2019re a solution that works for a lot of people. If you\u2019re tired of juggling two sets of tools, overpaying for tooling, or losing time hunting for the right tap or die, let\u2019s chat. I can help you figure out if multi-purpose threading tools make sense for your specific jobs, or if you\u2019d be better off with dedicated tools. No pressure, no sales pitch, just real advice from someone who\u2019s been in this industry for 12 years, fixing tool problems and saving shop owners money.<\/p>\n

    <\/p>\n

    Don\u2019t overcomplicate it \u2013 ask yourself: do I need one tool for two jobs, or two tools for one? For most of you reading this, the answer\u2019s the first one. And when you\u2019re ready to explore your options, hit me up and we can work out what works for your shop.<\/p>\n

    End Mills<\/a> References<\/p>\n

      \n
    1. ASME B1.1-2019, Unified Inch Screw Threads (UN and UNR Thread Form)<\/li>\n
    2. Machining Design Guide, "Multi-Purpose Threading Tools: Applications and Best Practices", 2022<\/li>\n
    3. Cutting Tool Engineering Magazine, "Hybrid Threading Solutions Reduce Tooling Costs for Job Shops", Q3 2021<\/li>\n
    4. ISO 68-1:2010, General Purpose Screw Threads \u2013 Metric Profile \u2013 Part 1: Principles and Basic Data<\/li>\n
    5. Society of Manufacturing Engineers (SME), "Tooling Optimization for Small Volume Production", 2020<\/li>\n<\/ol>\n
      \n

      Small Craftsman (Shandong) Machine & Tools Co., Ltd.<\/a>
      Small Craftsman (Shandong) Machine & Tools Co., Ltd. is one of the most experienced threading tools manufacturers and suppliers in China, also supports customized service with low price. Please feel free to buy bulk high quality threading tools in stock here from our factory. Contact us for pricelist.
      Address: No.9 Quanxin Rd., Sishui Economic Developing Zone, Jining, Shandong, China.
      E-mail: 6196@ocutchina.com
      WebSite:       https:\/\/www.ocutooling.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

      Hey there, let\u2019s cut to the chase \u2013 if you\u2019re in manufacturing, construction, automotive, or literally … Can threading tools be used for both internal and external threading?<\/span>Read more<\/a><\/p>\n","protected":false},"author":60,"featured_media":3473,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3436],"class_list":["post-3473","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-threading-tools-42d0-c9a24f"],"_links":{"self":[{"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/posts\/3473","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/users\/60"}],"replies":[{"embeddable":true,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/comments?post=3473"}],"version-history":[{"count":0,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/posts\/3473\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/posts\/3473"}],"wp:attachment":[{"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/media?parent=3473"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/categories?post=3473"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.processfolks.com\/blog\/wp-json\/wp\/v2\/tags?post=3473"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}