Methods of broken tap removal

[560Dennis]

6 possible methods of broken tap removal

6 Effective Ways to Remove Broken Taps - Practical Machinist

Broken taps are never a fun task to deal with, but getting them out is necessary to save the part. Here are several different methods to get the job done.

www.practicalmachinist.com

 

[40Mule]

Tap extractors are the best way to go in most cases. They work well when it is a clean break of the tap. If the tap has shattered at all the pieces will bind up. You may need multiple replacements of the fingers as they bend and break easily. I have used these literally a thousand times at work. Blow the hole out well, use oil and try a left to right motion and you may get lucky. I have also used the last one. We called it a tap burner. Would burn a hole through the center of a tap or drill with coolant running through the center of a rod that burnt up as it made its way through. Used a pink coolant called Cimcool that you didn't want to breathe the fumes. Still had to pick out the edges with sharpened to a needlepoint drill and not tear up the threads. The chances of just breaking out a tap or drill by beating on it are slim unless you want to destroy the threads.

 

[tom upton]

Have removed lots of tough ones by plug welding washer on and then a nut on the washer. Some people tend to break a lot of taps when hand tapping. We had a Millwright apprentice at work that you could pretty much guarantee if he had to tap anything under 3/8 holes he would break at least 1 tap! Prior to CNC we used to do a lot of machine tapping with a tapmatic. Pretty slick tool and I dont ever remember breaking a tap with one as you set the clutch for the size of tap. Seems with cnc guys break more taps than the old tapmatic??

 

[Mike(NEOhio)]

I've been through most of the methods in the article but the most amazing to me was an old-time welder in the GM plant when I was an apprentice. He could burn them out as small as 1/4 using an oxy-acetylene torch with a small tip. He heated the end of the tap then goosed the oxygen valve open and back quickly to blow out the center of the tap body leaving the threads intact.

 

[Keith True]

A few years ago I had a machine for removing broken taps.I believe it was called a Buzztap.The chuck,or head,had to be used in a drill press or milling machine.It used air,and possibly water in the operation.I believe it was some kind of EDM process.It had little sacrificial wires that did the work.I never heard of one and never used it myself,but when I advertised it for sale a lot of people came out of the woodwork to buy it.Reading the manual I got the idea it disintergtated the metal rather than melting it.

 

[Mike(NEOhio)]

A few years ago I had a machine for removing broken taps.I believe it was called a Buzztap.The chuck,or head,had to be used in a drill press or milling machine.It used air,and possibly water in the operation.I believe it was some kind of EDM process.It had little sacrificial wires that did the work.I never heard of one and never used it myself,but when I advertised it for sale a lot of people came out of the woodwork to buy it.Reading the manual I got the idea it disintergtated the metal rather than melting it.

I saw one of those demonstrated in our shop, different name though. Basically a crude EDM, in stead of the tank flooded with dielectric it relied on a wet rag wrapped around the electrode. They didn't buy it, we already had a good EDM machine.

 

[40Mule]

What I learned was NOT to break them. You are far better off to lose a thread or two at the top of the hole than start it crooked and break it four or five threads in, totally mess it up and think of drilling it oversize and trying it again. Start with a nice chamfer at the top as it makes it easier to start. Hand tapping is hard without practice. If you even think it may be crooked, Stop. If you have to, walk away and come back to it. Take five times if needed but get it straight. On an engine it is very easy to drill into the water jacket or oil passage if you try to drill oversize. I learned on cast iron V 8's. We used hand held air driven drills with a reversing chuck. Push, it went in cutting threads, pull and it reversed backing out using plenty of oil. . easy if the hole went through but a little harder on blind pan rail holes. We had seven different sizes and on a bad day may run four to five hundred holes. Might be a head bolt hole and a panrail hole or two and maybe a front cover too. They were all machined on different operations and could run up to fifteen repairs before the probe station caught them and sometimes, they didn't until the setup man did a check and found it. Some of you won't believe it but I may have tapped fifty thousand holes this way. We built one million engines per year at more than five thousand per day assembled. I had one block where I took seventeen broken taps out of it. My personal record and hated every one of them. It took four or five lines doing the same operation to keep up. We ran six or seven hones, running four bores at a time right next to each other to keep up. You hear twenty-four or twenty-eight hones at the same time, and it was a noise that is impossible to describe. A learning experience almost forty-eight years ago. We called them cases, only outsiders called them blocks.

 

[drsportster]

My college is getting an EDM machine .They did not mention drilling a series of small holes around the broken stud and then extracting the mess and rewelding in the hole {works great on aluminum]

 

[40Mule]

It took a lot of training when we went to aluminum. Cutting taps to roll forming taps. Fractions to M size. Instead of thousandths we now used microns. I think our old burner ran on 440. Two knobs, one to nine for power level and another for vibration of the head and rod. The vibration controlled downward speed and helped to keep the rod from sticking to the tap like a welder. You turned coolant on with a rag around it and the rod not touching or it would weld solid and turn off. Looked like a lightning storm behind that rag. Would throw sparks like a welder and coolant flying if it came off. Different size rods for different taps and power level. This was fifties or sixties machine. Left burnt slag that flushed out with the coolant. Heavy duty with a lot of use. I see there are little ones in ads. New machines dropped repairs to almost nothing. We no longer repaired we scrapped them.

 

[kencombs]

How to remove broken taps? No specific tools for that in my home shop, so it's like arguing with the wife, lots of techniques, none of them work, I almost always lose. Seriously, I've never been able to get one out of a blind hole. Through holes, maybe. I broke a 1/4-20 last week. Old, dull tap in 3/8" plate broke when only maybe 2 full turns in. Got that one out by using a punch from the back side to break it. Not many threads to ruin that way, and the new, sharp tap cleaned them up.