Getting a busted tap out

[kcstott]

There seem to be one of these questions every few months. So I decided to take a snap shot of my busted tap and how I got it out.

FYI I do not recommend wasting your money on tap extractors. If you broke a tap and can get it out with a tap extractor that means you dropped your part and the tap hit the floor first.

The number one reason taps break is not having it square to the work.
the number two reason is a two part reason, Either a dull tap with to much force applied or not clearing your chips properly.

This is the reason I spend good money on gun fluted taps. they push the chips forward of the tap and out the hole or to the bottom of the hole if it's a blind hole.

Spiral fluted taps allow chips to clear the hole like a chip off a drill bit.

Now on to how to extract a tap.

First thing you need to figure out is, Is the tap tight in the hole or is it loose? that will tell how much of a PITA it's going to be to get it out.

Then how much of the tap is in the hole? Did you break it off at the shank or did you just bust the tip??

Again this determines what it will take to get it out.

If the tap is loose but not budging when you try to back it out it's stuck on chips most likely. If the tap is large enough use a center punch and try to drive it out backwards until you can get enough exposed to grab with vise grips and get it out the rest of the way.

If the tap is tight well it was probably dull and you should have thrown it away.

try the above method with a center punch to get it out.

if that fails you will need to seek out a EDM shop or learn how to weld.



If you can get to the tap build up a little bit of weld on it and then weld a screw to the weld. soak it in cutting oil and very carefully work the tap back and forth to clear the chips then try to back it out. you may need to work it a little bit to get it freed up but it should come out. If your weld breaks try again. Simpla sa that.

That busted tap above was mine. I got in a hurry on my lower and didn't clear the chips. So i paid for it. It's been a while since I broke a tap but we are all human.

[GMG]

I've seen that done on broken bolts that that hold accessory brackets on engines.

[Bullets&Whitewalls]

Good stuff! I'm long over due for another one of those.

[highintel]

I learned this lesson the hard way once. The only choice I had was EDM. Not only did EDM burn through the tap but it burned right through my wallet as well.

[1flhtk4me]

That's a high spiral tap in the pic,what mat'l were you tapping?
If used on aluminum,it should not have broke.

[kcstott]

That's a high spiral tap in the pic,what mat'l were you tapping?
If used on aluminum,it should not have broke.

What did i say? "I got in a hurry and didn't clear out the chips"

Yes you can break a tap in aluminum as i did here.

the point is to know what causes a tap to break and then don't do it. the point of being a good tool maker is taking risks based on experience, well I took a risk and had to fix it.

[tujungatoes]

Pshh...amateur.

[1flhtk4me]

What did i say? "I got in a hurry and didn't clear out the chips"

OK, I did not read read the bottom part.

Just saying high spiral taps are suppose to clear the chips, exiting out the top so you don't have to "clear" them.
Yes I guess you may have to depending on the depth of thread.

Pshh...amateur.

If your referring to me,I don't think so.
Machinist/tool maker for 37 years.

[kendog4570]

Good thread KC.
One way to help clear chips in a blind hole is to drip candle wax into the hole prior to tapping. Go ahead and fill it up. As the tap cuts the wax and chips are hydraulically forced out the flutes. Leaves a nice clean bottomed hole. Throw a little of your favorite tapping juice in there for good measure, and of course use proper procedure to make sure the tap is square and supported.

[geedavell]

These help to keep the tap square when you have room to use them.

[milotrain]

This is going to sound strange but I stopped breaking taps when I started power tapping. As long as it's not Stainless, Prehard, or a blind hole I power tap in a drill chuck in the mill or in a drill chuck in the lathe with the tailstock or quill loose. Works perfectly.

I do however have some very nice taps, and I use copious amounts of proper cutting fluid. Not to suggest that any of those would save us from ourselves but for new guys, you can't spend too much money on good fluid and good taps.

I just powertapped a 2" deep 1/2-20 through hole in the lathe in some 12L14, with a vintage sharp Brubaker tapered four flute at 45rpm, with CoolToolII. It was perhaps the smoothest tapping operation I've ever run. It was magical. I was mesmerized watching it, and spinning the tap back out there was no resistance.

[tujungatoes]

If your referring to me,I don't think so.
Machinist/tool maker for 37 years.

Nah...just bustin'. KCstott's chopps because he's a buddy of mine and I know he's forgotten more about metal working than I'll ever know

Good thread KC.
One way to help clear chips in a blind hole is to drip candle wax into the hole prior to tapping. Go ahead and fill it up. As the tap cuts the wax and chips are hydraulically forced out the flutes. Leaves a nice clean bottomed hole. Throw a little of your favorite tapping juice in there for good measure, and of course use proper procedure to make sure the tap is square and supported.

Interesting idea Ken. I'll file that one away in the memory banks.

[1flhtk4me]

OK thanks Tujungatoes.


Some more tapping tips....

Use roll/form taps for blind holes in soft materials.No chips.
Or use high spiral taps.

Drill the minor diameter to the high side.Most drill/tap charts don't give the tolerance of the minor dia.The Machinists hand book does.

For thru holes,use 2 or 3 flute spiral point plug taps.

Taps also come on different diameters.They are designated by the GH number .....GH3,GH4,GH5 or +.005,etc-. for cut taps.BH numbers are used for roll/form taps.The larger #'s are bigger on dia.
Larger ones are typically used for material that is going to be heat treated.

Bottom taps are used to maximize the depth of the hole after a plug tap is used.

Use a tap guide as said before if tapping by hand.

[kcstott]

Ok Spiral fluted taps do bring the chips out like a drill bit but on tougher aluminum alloys like 7075 the chips tend to be be short and clog the tap.

Regardless I screwed up and if i would not have gotten in a hurry to finish one little hole I would not have needed to take the time to get the little bugger out.

now the tap was driven in deeper the the flutes would allow chips to clear. and the tap was necked back to allow for a deep thread. this was the second pass in the hole and the threads were about an inch deep and the tap only has 3/4" of flute.

I hate tap guides and only use them when i have to.

Now the Idea of wax in the hole to push out the chips is a damn good one.

Milotrain your smoothness of the taping was due to 12L14 and not much else. You could tap that stuff with a dull tap and it would work.

Try that in mild steel and you won't be so pleased.

And Kris Tanks buddy