Help with broken drill bit
OK folks, how do you remove a 1/8" drill bit from aluminum that broke just below the surface face? Meaning nothing to grab a hold of...
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Drill in from the other side and try to tap it out. Get some carbide spurs from your dentist and whittle away.
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forgemonkey thank you sir that would work except I don't have a MIG welder and love2shoot I can't drill from the other end, it is not gonna be a through hole... the aluminum around the bit for about a 1/4 inch is also gonna be removed so maybe I can ignore that one hole with the bit and drill out around it with the next larger bit size to continue removing the metal? This is my 80% lower project I'm working on and this was one of the last few holes for first pass. I finished the other holes around it with another bit...
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Use a 7/64 two flute carbide endmill and go right down on it carefully. If you have a left hand carbide endmill the better. Depending on how precision your chuck and quill is , you should not hurt the original hole size at all.
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Can you get a set of C clip pliers to fit? Put the little prongs that would go in the holes on the C clip down in the flutes of the bit and hopefully you can 'un-screw' it.
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If you have a cut off wheel, you can sacrifice a larger drill bit, and grind a slot the same size as the stuck drill. Starting it will be a little tricky, but I have removed many of them this way. You are essentially removing the material from around it so you can grab it.
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ive used the c clip pliers to turn out the bit. also you can stick a couple of small allen wrenches in the bit groves, grab them with a pair of needle nose pliers and try turning out.
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They make broken tap removers that size I believe. A two flute that size might work.
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Try a small nail and tap on one of the flutes to try and get it started back out until you can grab onto it.
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Usually a drill breaks because it is chip bound or hot. You are not going to get a high speed drill bit out of a blind aluminum hole without damaging the parent metal and ending up with an oversize hole.
Your best bet is a local machine shop that can EDM it out.
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Drill the High speed bit out with a Titanium or cobalt drill bit
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And remember, next time Boelube.
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I would try a left hand drill bit. Don
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That's why I stopped using high speed steel drill bits. I use nothing but Cobalt drills, Coolant/Lube. Your only hope is to step up to a cobalt drill, but your hole will not be 1/8" anymore.
Now taps are a different matter.
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"This is my 80% lower project I'm working on and this was one of the last few holes for first pass. I finished the other holes around it with another bit..."
Don't worry about it but don't hit it with your end mill or you'll ruin the mill. Cut as close to the broken drill bit as you can and use a DREMEL cutter to knock off the last of the aluminum and then pick out the broken bit.
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Mobuck That is a solution that I believe will work thank you sir! And thanks to everyone else that had suggestions some were possible and I have considered all of them and I was using cutting fluid (Tap Magic) but it was going so well for the first 20 something holes I got a little over confident and tried to get too much... it broke off below the surface and some of your ideas although good in theory, I couldn't try because the bit was too far below the surface and/or the 1/8 inch hole is too small to get anything in to try and turn the broke bit. Anyways tomorrow I will do as Mobuck suggested and that should do the trick.
Thanks again everyone.
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I’ve had similar problems with a broken winding stem in a wristwatch crown. Hard steel in soft (usually brass) surrounding. I use a strong solution of alum in warm water and let the crown soak overnight. It degrades the hard steel through photosynthesis or whatever the heck... electrolysis? and the hard steel crumbles away in the morning, to be picked out with a needle.
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When drilling deeper blind holes in aluminum with small bits, the chips tend to clog the flutes and then bind up tight.
Clear the chips more frequently and/or don't drill quite as deep. I know those instructions give directions for 'step drilling' between end mill cuts and it does get frustrating.
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Mobuck Thank you sir! Your idea with the Dremel worked, only took about 45 minutes to use the Dremel and remove enough of the aluminum around the broke bit to be able to use the smallest pair of needle nose I had to then grab it and twist it out! Thanks again to all of the ideas from everyone, just glad I can continue on with this project.
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Always happy to help. Sometimes the simplest of suggestions works.
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