Ever break a tap?

[Gord Baker]

Just start in a new spot or use metal banding to attach whatever you are mounting.

 

[Fields_mj]

Admittedly, I read the first page and jumped straight to page 6. I'm sure you're already fixed this by now, but IMHO you have 3 choices. First, if its an expensive part that you can't afford to start over on (I know you are not in this category), take it some where that has a plunge EDM so they can burn it out.

2nd option is to smash it with a hammer and a punch, and try to pick out the pieces. It's a PITA, and you risk damaging the threads which could require you to install a helicoil as part of the fix. Keep in mind that the tap is extremely hard and will damage your punch.

3rd option (this is what I would do in this application), smash it with a big hammer until nothing sticks out past the surface. Move everything 1/2" over and start again (or leave it in the same spot an use a different hole). FWIW, if the threads are not critical (ie, you plan on stretching the bolts appropriately to keep them from coming loose) always go at least one size bigger on your drill bit when you're tapping by hand. In this case, use a #6 drill bit instead of a #7. The extra few thousandths of an inch makes a big difference in how much effort is required. The more effort you're putting into it, the more likely you are to make a mistake and break a tap. Realistically, for a 1/4-20 tap on this application, you could easily use a #4 drill bit.

Also, make sure you're using an appropriate tapping fluid. For most applications, you don't have to get real fancy. I generally use ATF for mild steel and WD40 for aluminum.

 

[RandR10]

I've only ever broken a few taps over many years of using them. Usually not in blind holes, so putting a pair of vice grips on the other side and screwing it back out of the hole usually works for those. You should be able to do this if you drilled the hole clear through the side of your lift column. If not, read on.

The one tap I broke in a blind hole was in the head of my Bridgeport-clone mill the day I brought it home. Someone had broken an oiler off the side, and I messed up the threads pulling that out, then promptly wedged a broken tap back in the hole. I used a die grinder to flatten the jagged break, then worked at it for several hours with a few diamond core bits on low speed in the drill, keeping it wet with water the whole time. Eventually I got through the flutes to the taper, and with the pressure off the cutting edges no longer holding it tight in the threads, I backed what was left out of the hole with some mini needle nose pliers.

Moral of the story, don't use cheap taps, especially not in blind holes. I didn't have that size in my good ones, so like a fool I used a tap out of an old cheapo set someone had given me years ago, rationalizing to myself that all I was doing was cleaning up the threads. Boy did I pay for that mistake. I've used cheap taps where the metal is too soft. Those just don't cut and will actually twist instead of breaking because they were never hardened. Other cheap taps are too hard and brittle and will just shatter like this because they weren't annealed after hardening.

 

[gstrom99]

Tap extractors never work if you broke off the tap from binding, which it sounds like you did

This one did. The backside had to be smooth, so the column could slide up inside. All fixed, and wired, and working great.

 

[Flogger]

did break an easy out in a bolt once. I got it out by paying someone else...

My wife discourages the use of my paying someone else tool!!

 

[coast40]

I broke a 4-40 tap off in a small piece of aluminum a few years ago, and after some internet searching, I found a method using a concentrated alum solution. I mixed it up in a glass beaker and dropped the aluminum piece with the broken tap into it, and the next morning the tap was completely gone and the aluminum unharmed. Obviously though, that wouldn't work on a steel work piece.

I plan on doing this with a broken Irwin EZout stuck 40 years ago in a '59 Corvette 4 speed.

 

[gstrom99]

I plan on doing this with a broken Irwin EZout stuck 40 years ago in a '59 Corvette 4 speed.

Interesting. Let us know how that works, with pics...

 

[1Mech]

Have you seen these?

The Metal Disintegration process for removing Broken Bolts

Not sure what metal disintegrator is for you? Here are 5 easy steps to choose the right metal disintegrator to remove broken bolts

electroarc.com

I have used those when I worked in a machine shop years ago. Get it centered over the broken tap or drill bit and let it do it's thing. Similar to an arc welder, but instead of adding metal it eats it away!