Broken endmill

btboone

btboone

Joined
Feb 8, 2006
Messages
429
Today I had an employee break off a 1/32" endmill in a titanium ring. This ring gets holes all over the surface, like Swiss Cheese. It was just about flush to the surface, so I couldn't get ahold of it. I tried soaking it in acid knowing that the titanium wouldn't react much and the endmill should, but I started to run out of time, and it wasn't eating the endmill at all. Thinking about it now, it was a carbide endmill, so the acid wouldn't have done it, as it's pretty inert. I then realized that I could blast it with my laser welder if the power was high and the beam was tight. It blasted a hole right through it, and I was able to mill the hole cleanly afterward and ship the ring.

Is there something else that could have worked in such a situation? I suppose I might have been able to crush the endmill, but that would risk ruining the surrounding metal. Running another mill behind it would just tear up another cutter. I suppose the same issue would happen with taps. Is there a good way, short of EDM to get them out?
 
i use diamond dentist burrs in my dremel tool. i had to remove a broken carbide drillbit in a hole once and it they worked great.
 
I had a little carbide drill get stuck in an aluminum vacuum form mold last week. Similar situation, it broke off flush. And you know what? I ended up just leaving it in there. There wasn't a way to get it out without messing up the mold. It was .026" in dia and flush to the surface, and will be in there until the day the mold is scrapped.

I think a tiny diamond burr like Richard suggested might do the trick. You would need to program it to feed in a shallow helix because the very center of a burr doesn't cut well, so it wouldn't plunge well. And it would need a lot of RPM.

Good idea Richard.
 
a dremel works the best and at 30.000 rpm it will eat that carbide up. there was a guy here in town that had a so called harley repair shop. he messed up more than he fixed. one day he broke off an aluminum "T" that was epoxied into the aluminum crankcase. then he broke off a mack ez out trying to get what was left of the fitting out. 4 hours later and a lot of carbide and diamond burrs i finally get the ez out removed and what was left of the fitting. i'm pretty good at getting broken taps, end mills and similar items removed from holes in metal.
 
The last shop I worked at had a small unit (about the size of a mini-mill) that we called the tap destroyer. I can't remember the manufacturer but it worked on the same principle as a sinker type edm, using a small diameter carbon or brass electrode. It was a very precision, non "F" the part up method for removing a broken tap or drill. Very small diameter ones too.You could learn everything you needed to know to operate it in about 10 minutes flat. It was even on rollers so you could easily move it around. Here's a link to a unit that looks very similar to what our shop had. http://www.cosmos.in/tapremover.htm
The unit I linked too looks to be even more portable than the one I'm talking about
 
David Wesner said:
The last shop I worked at had a small unit (about the size of a mini-mill) that we called the tap destroyer. I can't remember the manufacturer but it worked on the same principle as a sinker type edm, using a small diameter carbon or brass electrode. It was a very precision, non "F" the part up method for removing a broken tap or drill. Very small diameter ones too.You could learn everything you needed to know to operate it in about 10 minutes flat. It was even on rollers so you could easily move it around. Here's a link to a unit that looks very similar to what our shop had. http://www.cosmos.in/tapremover.htm
The unit I linked too looks to be even more portable than the one I'm talking about
Click to expand...

My machinist friend here in town bought one similar to this on the bay for just a few hundred dollars. He needed it to remove a broken tap in an airplane engine case. He paid for it with just the one job.
 
Good stuff. Thanks guys. The laser was pretty impressive on a 1/32" but I don't think it would do so well on something larger unless I could slice it in half or something. I don't know the depth it could penetrate, but probably not a whole lot more than 1/8" or so. I have some diamond tipped tools for a Foredom but never tried them on carbide. The tap remover is a good thing to know about.
 
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