6 Effective Ways to Remove Broken Taps

July 25, 2019 8:18 am

 

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.

Center punch

Astro 1600 16-Piece Punch and Chisel Set

Use an extractor

Extractors are devices specifically designed to remove broken taps.

Walton Tap extractor

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

OMEGADRILL broken tap extractor

OMEGA 4 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 broke taps? Let us know in the comments below.

 

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31 Comments

    li class="comment even thread-even depth-1" id="comment-23883">

    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

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23884">
    chale44

    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.

    li class="comment even thread-even depth-1" id="comment-23885">
    Ant_topps

    If you’re tapping titanium or other corrosive resistant material, you can submerge the part in acid, which will resolve the tap.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23886">
    running20over

    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.

    li class="comment even thread-even depth-1" id="comment-23888">
    Chester the Molester

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23889">
    Dan

    Fastest way is waterjet, if you’re lucky to own one.

    li class="comment even thread-even depth-1" id="comment-23890">
    jond

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23891">
    John

    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.

    li class="comment even thread-even depth-1" id="comment-23892">
    Ron

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23893">
    Mike

    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.

    li class="comment even thread-even depth-1" id="comment-23894">
    Lurch

    A paste of alum and water will dissolve the tap into a brown sludge without harming the aluminum workpiece…

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23895">

    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.

    li class="comment even thread-even depth-1" id="comment-23896">
    Wingnut

    I have used a ball end mill to remove broken dowels. A ball end carbide burr will also do the job.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23898">
    Crazy Dave

    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.

    li class="comment even thread-even depth-1" id="comment-23899">

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23900">
    Hurco

    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

    li class="comment even thread-even depth-1" id="comment-23901">
    Panhead Bill

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23903">
    Daniel

    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.

    li class="comment even thread-even depth-1" id="comment-23905">
    SPHogger

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23908">
    dougspair

    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….

    li class="comment even thread-even depth-1" id="comment-23910">
    Bob

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23911">
    thom

    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] !!!

    li class="comment even thread-even depth-1" id="comment-23912">
    Re-Tired

    Down and dirty, wear a face shield, works for big ones: Heat up cherry red, throw ice cold water on it.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23914">
    Jeff

    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.

    li class="comment even thread-even depth-1" id="comment-23915">

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23916">
    j

    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.

    li class="comment even thread-even depth-1" id="comment-23919">
    MC2

    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.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-23920">
    Old machinist

    I actually made a deal with my dentist for his old instruments to pick out the broken pieces.

    li class="comment even thread-even depth-1" id="comment-23927">
    Smitty

    I ran a EDM back in the 80s . Used to burn the tapes in half , they would fall right out.

    li class="comment odd alt thread-odd thread-alt depth-1" id="comment-24087">
    Murph

    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.

    li class="comment even thread-even depth-1" id="comment-24189">
    Cpeters

    You can actually build your own EDM for very little money. We did this with an old alarm bell and bench power supply.

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