Broke a Tap while Threading new hole

   / Broke a Tap while Threading new hole #1  
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Furu

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Well I have done it now.:eek:

I was using a 10-24 thread tap to tap a new hole in A-36 steel and broke the tap.
Yes I was using cutting oil and backing off as I proceeded to cut the threads but it happened anyway.

What I have above the level of the hole is about an 1/8 inch length of 1/3 of the diameter shard of the sheared tap. With the three flutes on the tap it broke leaving only part of the shaft above hole level. I have tried to get it out but have been afraid to break off the remaining shard and making it worse. With the tap being hardened steel I doubt that I can drill it and put a screw extractor on it. I know that heat will loosen a stuck bolt but don't know if hardened steel expands faster or slower than the mild steel around it. Thought that heat might soften the tap and then I could drill it for a really small screw extractor.

While I am certain that no one else has ever snapped a tap :D I figured that someone could give me a good technique/idea as to how best proceed.
My last broken tap was over 20 years ago and thus my lack of anymore ideas on how to proceed.
 
   / Broke a Tap while Threading new hole #2  
Get a flat washer and place over the tap that is sticking out. Weld the washer to the remaining piece of tap. Put a nut over this and weld to the washer. Take out with a wrench.
 
   / Broke a Tap while Threading new hole #3  
2458n said:
Get a flat washer and place over the tap that is sticking out. Weld the washer to the remaining piece of tap. Put a nut over this and weld to the washer. Take out with a wrench.
Click to expand...

What he said.
 
   / Broke a Tap while Threading new hole #4  
They sell special "tap extractors" that have 4 prongs to fit around the tap in the hole. I personally have never had good luck with them because usually a broken tap is lodged in too tight to begin with. They would probably work okay if the tap broke because it got hit with something (and the remaing piece was loose in the hole) but that is rarely the case. Still though, it may be worth a try. It depends how much it's worth to you, as they aren't cheap I don't think.
 
   / Broke a Tap while Threading new hole #5  
If the hole goes through the part you are working With? It has happened that I have been using a punch and beaten the tap out. Since it is mild steel that can weld the hole and start over or drill up and use a larger screw or Helicoil
 
   / Broke a Tap while Threading new hole #7  
all i can say, is best of luck.
 
   / Broke a Tap while Threading new hole #8  
 
   / Broke a Tap while Threading new hole #9  
Furu said:
Well I have done it now.:eek:

I was using a 10-24 thread tap to tap a new hole in A-36 steel and broke the tap.
Yes I was using cutting oil and backing off as I proceeded to cut the threads but it happened anyway.

What I have above the level of the hole is about an 1/8 inch length of 1/3 of the diameter shard of the sheared tap. With the three flutes on the tap it broke leaving only part of the shaft above hole level. I have tried to get it out but have been afraid to break off the remaining shard and making it worse. With the tap being hardened steel I doubt that I can drill it and put a screw extractor on it. I know that heat will loosen a stuck bolt but don't know if hardened steel expands faster or slower than the mild steel around it. Thought that heat might soften the tap and then I could drill it for a really small screw extractor.

While I am certain that no one else has ever snapped a tap :D I figured that someone could give me a good technique/idea as to how best proceed.
My last broken tap was over 20 years ago and thus my lack of anymore ideas on how to proceed.
Click to expand...
Some considerations that could be important: How deep had you tapped before breakage. Did the tap break by twisting, or did you accidently jog sideways and break it. What was the last twist motion [in or out] before it broke?

... If the tap is not in deep you can probably loosen it by tapping using a "soft" punch made from a nail. Stay away from the shard at first. Put some penetrant down the hole and blow it out thouroughly to clean out any chips. Then tap straight down, then at angles alternately. Then tap gently back and forth on/near the root of the shard - first in the opposite direction you were going when it broke. - Repeat. - If it moves youve got it beat ... just be patient as you do back and forth motion.
Good luck!
larry
 
   / Broke a Tap while Threading new hole #10  
I have had good success with welding a nut onto the broken tap.
 
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