6 Effective Ways to Remove Broken Taps
We’ve all been in this situation: You are working on a part with internal threads. The job seems fairly easy. You select the right tap, start working on the hole, and then suddenly, SNAP! and the tap is broken inside the hole.
Why did this happen? Not enough cutting fluid? Poor chip control? There are plenty of factors that can cause tap breakage, but at this point they are irrelevant. The broken tap is inside the hole and you only have two options: get it out or scrap the part.
Since scrapping the part should always be your last resort, you’ll have to figure out a way to get that piece of metal out of the cavity. But how? Here are several different methods to get the job done.
Manually smash the tap
This method is the most cost-effective, but also the least effective. You can break the piece using a cold chisel, in case part of broken tap is above the surface, and then complete the job using a center punch.
Most machinist have cold chisels and punches in their toolbox, but in case you are considering purchasing a new set, this 16-pieces set from Amazon is what we recommend.
Astro 1600 16-Piece Punch and Chisel Set
Use an extractor
Extractors are devices specifically designed to remove broken taps.
Walton Tools 18001 Tap Extractor Set
They come in different sizes and with 2 to 4 “fingers” depending on the number of flutes. Using them is easy:
- Remove as many chips as possible from the hole
- Pick the correct extractor size
- Insert the fingers in the flutes as deep as possible
- Slide the collar down against the tap
- Use a tap wrench to turn it until the tap comes out
This method is fairly quick, but may not be very effective as the extractor fingers tend to twist off if the tap is too deep into the hole.
Mill the broken tap
One of the most effective ways to get rid of broken taps is to mill them out. Although there are several different endmills that you can use to get the job done, the majority of machinists who deal with this issue recommend using a ball endmill.
Grind it out with an Omegadrill
OMEGA 7 PC. Broken Tap Extractor Set
Omegadrills are uniquely shaped carbide drills, created specifically for removing broken taps. This method is very effective, but it requires a very rigid setup. You can purchase a set of Omegadrills on Ebay or through any premier distributor.
TIG welding
TIG welding is another practical way to remove the tap from the hole. The process, as clearly explained by Jodie Collier of WeldingTipsandTricks.com in the video below, consists of building up a head on top of the tap and then either grab it directly using vise grips or weld a nut on it.
If you are planning to do it yourself, you can either use a 309 or 312 rod.
EDM
EDM is probably the most reliable method to get the tap out of the hole. The EDM will burn out the center of the tap leaving just the cutting edges stuck in the threads, which you can then pick out by hand. Unfortunately, this is also the less practical method as most small shops don’t have access to electrical discharge machines.
Removing a tap from a hole is not impossible, but the process can be time-consuming and not always successful. That’s why it’s important to take all the necessary precautions to avoid that situation. Using the right cutting fluid and making sure that the taps are in good condition are two fundamental steps to prevent tap breakage and keep the machines running.
Do you know any other effective methods for removing broken taps? Let us know in the comments below.
59 Comments
I the past we would use an old Carbide End mill and run it at full speed into the tap. Friction would create enough heat to anneal the tap to the point it would easily machine out. We now use EDM.
Great segment as this is a industry problem
Long ago a master machinist friend showed me how to mill out a 2-56 tap in a complicated aluminum part I sure didn’t want to scrap. He showed me how to use the Bport quill in like 0.005″ increments with a good carbide end mill, and you would sort of ‘rap’ the quill feed handle sharply, over and over in 0.005″ steps until that sucker was gone. It worked beautifully; haven’t had to do that since, but it’s in long-term memory, for sure.
This method works great for me as well. Never have i had a problem yet.
If you’re tapping titanium or other corrosive resistant material, you can submerge the part in acid, which will resolve the tap.
I work in the asphalt industry using HardOx brand AR-450 plate,1/2-13 tap when they break I melt them out with the cutting torch.
STICK WELDER. put a rod of 6011 or 6010 rod in your stinger. Position and clamp in place a hunk of wood with a hole in it to guide your consumable. Set the Welder to ELEVEN. And shove the rod through the center of the busted tap.
If preferred blow out the whole tap and re weld the hole up and drill and tap again.
Fastest way is waterjet, if you’re lucky to own one.
https://www.practicalmachinist.com/vb/general/broken-tap-removal-chemical-methods-198135/ shows how chemicals can be used. I have a friend who has had numerous successes with removing studs and taps in Aluminium alloys.
I have drilled out dozens of broken taps–I generally use an 1/8″ carbide rod, the tip is angled in a 45 degree cutting angle-If I need to, I grind down the shank on a green wheel on my Grinder with the carbide chucked up in a portable drill–Just under the root diameter of the tap–Using highest speed
possible on a tight mill, I peck the tap out. I use oil–It smokes a bit–But it works great.I always grind off any points that taps break off in, as it will throw off the cutter.Always better to try and cut a flatter surface.
Have used solid carbide end mills to remove many taps and broken off bolts. Don’t let the end mill dwell on the part or work hardening will occur.
I have always used the “breaking up” method. Only problem was with Mac taps, they were not thou hardened. One big plus is it doesn’t matter if it’s upside down in a track roller frame or out in the open. Retired heavy equipment mechanic, 50+ years in the trade.
A paste of alum and water will dissolve the tap into a brown sludge without harming the aluminum workpiece…
In the jewelry industry we have diamond coated wheels, rods and others shapes that do a great job of removing a small hardened part. We frequently must remove broken drill bits from pieces of jewelry. Keep the diamond coated tips well lubricated with water.
Thanks for that tip from your specialty. I have a set of cheapo 1/8″ shanked diamond shapes from China that have surprised me several times with the successful uses I’ve put them to. Glad to hear of the water lube.
Regards,
Lawrence
I have used a ball end mill to remove broken dowels. A ball end carbide burr will also do the job.
A mig welder can also be used if either the tap isn’t too small or if it’s in non ferrous. The smallest I’ve done is M5 in aluminium. Took a few goes as it was a bit tricky lining the wire up spot on.
newbees should be very careful using carbide end mills to remove broken taps. You don’t want o make matters worse by breaking the brittle carbide mill in there too! remember to use air and light oil to keep cleaning out pieces of the tap.
If I had to guess I would say that most taps are broken in the first place by “freehand tapping”. This meaning no device to allow the tap to float and align itself with the hole. If a tap is driven into a hole at any sort of an angle, be it ever so slight, it puts undue stress on the tap. If you couple this with a ridged hold of the workpiece such as a bench vise you are courting a disaster.There are devices on the market that lets the tap align itself perpendicular to the workpiece. Tapping arms not only allow for a 90 degree approach to the hole, but the vises on these devices allow the workpiece to move as the tap enters and progresses through the hole. And let’s not forget the drilled and hardened tapping block made by many old time machinists that allowed the tap to enter at a 90 degree angle
The last time I had to remove a broken tap I used Diamond burrs, kerosene as a lube, and ran the spindle at 1800 RPM (Old gorton mill / engraver) The diamond burrs were free (used) from my friendly dentist. The burrs were too dull for tooth work, but just right for a #10 tap. It did take about an hour from start to finish, but it beat remaking the part.
A broken hss tap can sometimes be removed from copper or bronze with a cutting torch. you have to heat the broken tap quickly and hit it with the oxygen jet. The copper/bronze will conduct the heat away and won’t cut.
Once I went to my dentist and requested several dental diamond drill bits. Using a Dremel I ground around until I could get hold of the tap with needle nose pliers. Burned a bunch of used bits but what the heck there were free.
another way I’ve had good success with is the ‘Chemical method’…I used a product called Tap-Out…..dissolves enough of the tap to get it out with small pick or wire…Tao-Out is a solution of Nitric acid…be carefull….
4 flute, various size carbide mills, mostly cast offs from CNC machines which I touch up on a green wheel, hand fed, high speed. When I was learning I worked in a job shop with 12 other operators. It was my job to save the pieces. Since it is part of tool maker training I did it at other shop and trained people to do it at those shops.
electric “TAP EXTRACTER” …??…it’s been YEARS since i’ve seen one of these machines, but, they worked fine “back then” ..!!..It consists of a bench top machine similar to a small drill press that uses a hollow (copper, I think) “electrode which, when centered over the hole having the broken tap, and with water and electrical current flowing through it, is introduced into the hole at a pace that sets up an electrical discharge, (much like welding) thereby eroding the center of the broken tap, leaving only the flutes to be manually chipped out …I’m always looking for one..so.. if anyone knows of one for sale CHEAP”…[email protected] !!!
Down and dirty, wear a face shield, works for big ones: Heat up cherry red, throw ice cold water on it.
Canned air (held inverted allowing the liquid freon to come out directly on the tap) makes the tap extremely brittle where you can break it up with a punch.
Those Omega drills are easy enough to make out of scrap carbide – if you have access to a Deckel cutter grinder.
If you break a lot of taps, and can’t afford an EDM, consider making up a tap burner.
Harbor Freight sells a set of diamond grinding wheels, SKU 69658, 32397 for $9.99 that work great for grinding Omega drills. I use a spin index head with 5C collet to create the pyramid shape and old broken carbide end mills as stock spinning the grinding wheel in my Bridgeport with lots of water to cool the diamond wheel.
I have used carbide burrs in a dremel or other motors to grind out broken taps. Can take a while but with care saves an otherwise ruined part.
At my work we use very small taps (0-80, 1-72,etc…) If you have access to a waterjet (we have one on site with crosshairs) you can position over the tap hole and cut it out that way too.
How do you keep the jet from damaging the existing thread. In piercing through will it deflect while piercing. I have a water jet and I’m curious. Thanks,
I actually made a deal with my dentist for his old instruments to pick out the broken pieces.
I ran a EDM back in the 80s . Used to burn the tapes in half , they would fall right out.
In aluminum alloys, a favored method for very small taps is a hot solution of potassium alum to dissolve the broken tap. Watchmakers are very familiar with this method.
You can actually build your own EDM for very little money. We did this with an old alarm bell and bench power supply.
Please contact me. I would like to do this myself. Thank you.
50W fiberlaser.
Hatch at 0,02mm. Hakes about 20 /30 min to do a 3mm tap over 4 mm deep
I make a spade drill out of an old carbide drill or end mill. No fragile edges like on an end mill with flutes. You can easily keep it sharp on a pedestal grinder, which you need. You can tell when it’s getting dull, (no chips and force). As in most cases other than EDM it’s tedious but, with patience it will work.
I have a lot of luck with a left hand carbide drill. Hooks up with tap an comes right out.
Alum in boiling water will rot out taps in non-corrosive materials.it does take longer but all that is left of the carbon steel is black powder,not sure if this is iron or carbon that is
Broken taps in aluminum can be anodized out. All you need is a battery charger and battery acid..
Silikroil penetrating oil will help lubricate the tap to make it easier to remove with an extractor. Kano Laboratories makes it, good stuff.
I take a broken carbide e-mill shank and grind it to two points @ 90 degrees about 60 degrees, spindle at 1800 in a milling machine and cut it out.
Under no circumstances should you use a hammer and punch to break up a tap. Taps are hard on a piece breaking off has the potential energy of a bullet. It can and has pierced people’s skin and became embedded in their hands, arms and other body parts. This is a very dangerous thing to do.
I always use Tig welding to remove a broken tap, even in aluminum. The problem is not every one has a Tig welder.
The Rice Cripsie jingle, Snap what a happy sound. There is nothing happy about snap, you just broke a tap.
A master machinist once schooled me in milling a small (2-56) tap out of a part I REALLY didn’t want to start over on; using the quill stop on the Bport, a half a thou at a time or maybe it was one thou at a time, sort of sharply ‘rap’ the spindle travel handle against the stop, over and over until you’re at the bottom. I used a decent flat end carbide mill as I recall. I’ve managed to not have to do that again, since! But it sure did work.
We use our Flow waterjet. Works great!
Usually a broken tap is the result of hand tapping in an awkward place. And generally the awkwardness precludes EDM, or a machine set up, especially in maintenance work
For through holes #10 taps (5mm) or larger, taps can frequently be burned out without sacrificing the threads in the bore. Plasma is most effective with the caveat: You need sufficient machine current to fully clear the body of the tap out of the hole in 1-2 seconds.
In all of my forty-five years, I have broken forty pounds of taps.
But, I have never scraped a part because of that. Sometimes, a small broken 1.5 mm screw can be removed using Kroil and tweezers. My favorite is EDM, but carbide milling a hole through the minor flute diameter has never failed. A broken screw, I LOVE left hand drill bits.
After reading all 45 replies, I wonder how many of these men are OLD SCHOOL.
Guys in there 50s or retired. Let’s face it.
We are a dying breed.
40 years out of Tech School and we can’t find good young men that wants to learn the trade. I see it every day, all they want to do is push a button, sit on there Ass and play with their phone.
Sad world out there!
Many times a tap breaks because it is dull and requires to much torque to drive it.
If you have done enough hand tapping, you can tell a sharp tap from a full one. The dull tap will be springy, both going in AND coming out, so if you reverse the tap and it doesn’t turn easily coming out, toss it. When a tap is sharp, it cuts crisply, like tapping an idea cube!
I worked in a Hi Performance engine shop years ago. We chased every hole in every block and head that we worked on. I convinced the rather frugal owner that the best place for a dull tap was in his competitors tool box. He became a believer.
I like McMurph’s comment. Sad but true. I read most of these wonderful posts, but, didn’t catch using heat to expand to part, to loosen the grip on the tap. Only a few tenths, but, maybe enough before resorting to all the other incrementally expensive and successful options. I have a friend with EDM. Used various lube sprays to loosen it, the tap extractor fingers, diamond saw to slot the tap for a screw driver! The hammer method to elongate the host material, hoping to save the part, the axial alignment jig for my drill press and mill, the tapping head, the right fluid, touching up tap with a slip stone as often as you use the tap, periodic replacement of old Betsy, and oh yeah, patience. Ever heard of that? A great post for those who are younger and want to learn the real truth. Thanks to all.
I’d just like to point out that aerospace parts may have restrictions on EDMing and Welding. As a guy who likes it when airplanes stay up in the sky until they want to land, please look hard at the print notes for EDM/Welding allowances. If it doesn’t say “EDM allowed”, it isn’t allowed. Get the Quality Manager involved beforehand plz and tnx.
Hand grinding old carbide drills to spade end has worked for 40 years for me
Tig Welding works sometimes., taking a bit of the tap at a time as the heat usually fractures the hardened tap causing it to come out in pieces. It the tap breaks while in the mill, I use the carbide EM trick. Everyone I worked with always said to run the mill as fast as it would go. For me that usually ended up destroying a lot of mills. I reasoned that I should run it slow as you always run at lower SFPM on harder materials. Slow worked for me using either ball or flat EM’s at 8-10 SFPM, 0.001 IPR, and constant compressed air to blow away the chips. Be ready to stop quickly as the EM may self-destruct when the outside of the tap starts to fall out. Try slow… the next time!
I’ve probably removed over 100 taps in my career using a TIG welder. As long as the tap isn’t cracked along the centerline it works pretty good. I use .030″ stainless safety wire as filler metal and sharpen the tungsten to a fine point. This process works best on aluminum but I’ve removed them on steels and stainless steels as well.
I used diamond burrs in a mag drill for remote pieces. lubricate with water
The candle trick works almost every time. We have been using bees wax since a Great Lakes ore boat engineer hipped me up to it over 40 years ago. – Fact is if you look in almost any marine engineer’s tool box you will find a chunk of bees wax. Brake fluid (not brake CLEANER) is another thing they use all the time at the steel mill but I have not personally used it.
Just on an unrelated note do not allow brake cleaner inside any shop where there is any welding or other sustained arc,,,,even outside… It will decompose into phosgene gas in the presance of UV light, and only one slight whiff will screw you up for life. – Look it up if you don’t believe me.