Removing Broken Drill Bit

While drilling out 1 of 3 broken bronze screws that sheared off from one of the swim platform brackets, the cobalt drill bit caught an edge and snapped off inside the hole. Tried drilling that out with a slightly larger cobalt bit but it quickly went dull with no apparent progress made.

Outside of simply putting West System over it and drilling a new hole, anybody got any nifty tricks for removing a broken drill bit that still has part of the screw behind it? Was thinking of getting a punch and whacking the ba-Jesus out of it, but thought that may do more damage to what is still holding screw in. Appears there may be an encapsulated metal sheet with threaded holes that swim platform bolts pass thru on stern.

Also - I cannot get at hole from inside boat - the fuel tank is about 2 inches away from stern where this screw passes thru - so can't attack from that side. Thanks Guys - Scott

OUCH! That's the trouble with carbide/other hard drill bits (and easy-outs!). They are quite brittle and break much easier than regular bits. I assume it's a relatively small bit - 1/4 or maybe 3/8? Even so it MIGHT be possible to use a small pointed punch/chisel and try to set it as close as possible to the edge of the broken bit and tap it with a hammer, trying to turn it in the opposite direction and have it withdraw itself.

Failing that, I would leave the bit/screw remnants for posterity, flll over it and redrill a new hole.

Good Luck.

It was a 1/4" bit that snapped. I found these nifty drill bit extractors from a 4x4 site - http://www.peterson-international.com/safeandvault.htm

Think a punch would be cheapest way to start.

You'll never be able to drill it out except maybe with a carbide bit, and I can promise that will not work with a hand held drill. The smashing trick may work but with the risks you describe. I think Hatteras embedded an aluminum plate in the transom to attach the platform, so the stuff that's holding the bronze is fairly soft. Heat also won't work for obvious reasons.

The only thing I can think of is to see if you can get some stiff wire and drive it into the flutes. Then grab the ends of the wire with pliers or clamp some plates to it and see if you can twist it backwards a little and free up the edge that it's hung up on.

If you're comfortable enough with fiberglass work, you might want to consider using a hole bit around it. Then just fill the hole and start from scratch. Especially if you can make the hole small enough where it will be covered by the platform bracket.

Cool tool at Peterson website..good post...thanks

I have had success with spot welding broken bits say to a grade 8 bolt, the trick is to get a connection to the broken bit in something not ferrous.

On steel I have grounded the area and shoved an insulated bolt connected to my welder onto the broken bit and let it weld itself and then wrench it out.

This is a little trick that we use in our diesel shop to remove broken headbolts without removing the head. It has never failed and saved many a customer the cost of removing and re-installing a cylinder head

You need to be able to ground directly to the drill bit,it can be done with an old screwdriver or even a nail connected to the ground lead.If you do not,you risk welding it to the surrounding metal.

Using just a large electrode, with a small piece of vinyl or rubber hose around the end to insulate it from arcing on the wrong thing,hold the electrode directly on the broken piece.Have someone quickly turn the welder on then off. If you had experimented with amperage and got it right,before trying the real piece,the electrode will be welded to the broken bit. Remove the electrode from the holder,bend the top to make a 90 degree handle and hope for the best.
Good Luck Tony

Sounds neat - If I tried that I'd probably end up with a drill bit, electrode, and screwdriver all welded together and all of it still stuck to the boat! :)

That is a neat trick and just the excuse I need to buy a welder! Actually friendly with the yard manager, just may be able to buy into this experiment with his welder. Thanks for the tip.

If the broken drill bit is into fiberglass. Try using a small wood plug bit and drill it as if you were making a plug. Drill only deep enough to reach the drill bit. Dig out the material which is now like a screw plug. Be Careful side-loading the drill bit on smaller bits or you could snap it off removing the plug material. .25 drill is pretty strong. I wouldn't to much about side load with a .25 drill, but in general. Then you can get a hold of the drill bit with short needle nose pliers. Don't use vise-grip pliers on it. They will tend to crush the bit and snap it. Don't hammer on it you will break it off deeper. A shot of tap magic on the drill bit will make the bit break free easy-er. Remove it counter clockwise and good luck. Never use a carbide drill bit when there is the chance of an interrupted cut. Any type of carbide bit will not stand up to the shock of an interrupted cut. Use the smallest plug bit you can. Then you can easily plug the hole. It works for me.

BILL

My vote is for:
1) the drill bit extractor
2) a hole saw or plug cutterl, to cut a core around the bit, then go after the bit. You can re-build the hole with fiberglass and resin to good effect. Entire transoms are grafted on to motor yachts to make CP MY's, so re-build a small hole is possible. But ensure you include fiberglas mat to provide strength.

3) The issue with tack welding a bolt or electrode to the broken drill bit is a good ground, so that, although the embedded plate may not (or should not be) be grounded, the bolt you're chasing does not weld itself to the embedded plate. Make sure you get help with someone experienced with welding gear. Oh, get some goggles...you don't want the sand-in-the-eyes effect for a week if you catch the arc close up with bare eyes.

Leaving it? I am too picky- I would know its there and it would drive me crazy over time.

Actually I would think somebody could make a kit and sell it it, yes I have done the tubing bit too, its never the same and even the heat alone is sometimes enough to change the grip in the material. Also as an off the wall thought was if somebody had some really cold stuff like liquid nitrogen and pour it on the bit and wack it with either a pneumatic bit or something hard enough to fracture it.

As a master fabriactor, I've removed broken/stuck/shattered/ blind hole pins/taps/drills/etc a zillion times.
If it's a tap, tig weld onto the back of the tap, making sure to weld all the pieces together (they usually shatter lengthwise) and buld up a "T" handle drop by drop. The heating/cooling cycle breaks up the molecular bond at the point where the tap is sticking and anneals the tap so it doesn't shatter more when you twist on it. After it cools, apply Moly Dee (accept no substitutes!) and the offending part can usually be turned out with fingers. If you don't get all of the part the first time the Moly Dee can easily be washed out with a squirt of acetone so you can try again. Most oils can't.
This only works on a gounded part of course.
For broken drills/pins and so on, make a mini slide hammer with a pointed tip. ground the slide hammer (grounded/conductive parent part not required) and weld it onto the end of the pin. Let cool and tap out the stuck part. I've used this method on 1-1/2" drills in huge die plates and 1/64" pins in the brass body of $300,000 microscopes, and everything in between. The guy who broke the thing (the guy who's ass you're saving) thinks you're a genuis.
If you don't happen to know a weldor who's NASA qualified to weld space flight hardware (like me) find the guy that builds towers in your local yard, he can probably help you out.

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Originally Posted by luckydave215

As a master fabriactor, I've removed broken/stuck/shattered/ blind hole pins/taps/drills/etc a zillion times.
If it's a tap, tig weld onto the back of the tap, making sure to weld all the pieces together (they usually shatter lengthwise) and buld up a "T" handle drop by drop. The heating/cooling cycle breaks up the molecular bond at the point where the tap is sticking and anneals the tap so it doesn't shatter more when you twist on it. After it cools, apply Moly Dee (accept no substitutes!) and the offending part can usually be turned out with fingers. If you don't get all of the part the first time the Moly Dee can easily be washed out with a squirt of acetone so you can try again. Most oils can't.
This only works on a gounded part of course.
For broken drills/pins and so on, make a mini slide hammer with a pointed tip. ground the slide hammer (grounded/conductive parent part not required) and weld it onto the end of the pin. Let cool and tap out the stuck part. I've used this method on 1-1/2" drills in huge die plates and 1/64" pins in the brass body of $300,000 microscopes, and everything in between. The guy who broke the thing (the guy who's ass you're saving) thinks you're a genuis.
If you don't happen to know a weldor who's NASA qualified to weld space flight hardware (like me) find the guy that builds towers in your local yard, he can probably help you out.

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I love this site...super-duty smart guys and their knowledge. Also, I am jealous...so many cool things in life that we can't know and do. Of course I am at the 3rd stage of learning in life- I know there is someone smarter that me on all topics and I want to know who they are and where they are so I can get them for my project!

You guys are a riot why don't you recomend a laser denaturizing atomic ray gun that would be about as usfeull. The poster's a guy working on his boat that had a bit break off do you really think he's going to hire someone with welding equiptment to come down for this?

Trojan's got the best idea something that will probably work and can be done without the help of NASA

Brian

Well, I guess that puts the kibosh on my suggestion to call up the local general Aviation airport and see if there is a tech available with a Spark Erosion machine or EDM (electric discharge machine).

Instead, why not try to tap two thin nails down into the flutes, grasp them with vise-grips and try to turn out the drill. You don't need much grip, just enough to break the drill free, anyway it's worth a try....

What a great idea! Why didn't I think of something like that? :rolleyes:

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Originally Posted by Westfield 11

Well, I guess that puts the kibosh on my suggestion to call up the local general Aviation airport and see if there is a tech available with a Spark Erosion machine or EDM (electric discharge machine).

Instead, why not try to tap two thin nails down into the flutes, grasp them with vise-grips and try to turn out the drill. You don't need much grip, just enough to break the drill free, anyway it's worth a try....

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1st paragraph interesting! 2nd- the two nails are similar to the configuration of a broken drill remover, however, with sturdier metals.

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Originally Posted by Brian Degulis

You guys are a riot why don't you recomend a laser denaturizing atomic ray gun that would be about as usfeull.
Brian

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What is your experience with this? Where can you get one of these (lol). P.s., if you can write the specs (above), someone can probably make one!

Geez... ya never heard of a L.A.D.A.R.G. before??? I thought that was stardard equipment on an old Hatteras! LOL ws

Use a potato

I think Krush has the solution. I second the potato!

Seriously, you can cut the hole bigger and grab the bit to remove it. There is no structural issue with doing that. The aluminum plate that is glassed behind each swim platform bracket is substantial, like 3" wide. Once the bit is out, just fill the enlarged hole with thickened epoxy and redrill to size.

Go Krush. great Idea. Like a light bulb came on.

Thanks everyone for all the great suggestions. Here's what I did - I bought a finishing nail punch for $2.99 at hardware store that already had a pretty good point to it. Since it was cobalt bit that was pretty brittle I was able to shatter it with nail punch and hammer and get it back out the way it went in. Went at sheared screw once more with a slightly larger bit and got it out – Success!.

I agree with spartonboat1, I always find it really interesting when people, like luckdave215, tell what they have done. My father in law, who was in the Navy during Vietnam, was in town for the weekend. We went to the Cradle of Aviation of Museum in Garden City, New York on Saturday - what a display of both aircraft and space ships. One of the best museums I can recall visiting. Didn't know that all the lunar landers where made in Bethpage, Long Island. They even had the real Lunar Lander # 14 in 'life like" display that was suppose to go up on Apollo 18 before it was cancelled (Apollo 17 was last one). Dave - I think of you .

Yesterday we went to the Intrepid Sea and Space Museum (Air Craft Carrier) which just came back from being refurbished. Right next to it is a "Growler" submarine - immediately thought of yachtsmanbill and his older boat “Growler” - did he serve on this same sub or is that the make of that boat? This sub was old but bad ass – had two missile silos on front. The missiles actually slid aft horizontally onto a missile launcher that is the raised and pointed at target (this all apparently happened when the sub surfaced). As a quick aside – was talking with one of volunteers (a veteran) who said they are Not suppose to talk about guns and war, and here we were on the deck of an aircraft carrier with a 30 year history filled with about 70 different fighter jets and helicopters. As if future wasn’t already bleak enough. Anyway – thank goodness for this web-forum where men can be men and talk about such things as L.A.D.A.R.G’s and potato’s.

My pal gators barber was a bow gunner (anti aircraft) on the Intrepid. Old Harve doesnt mind talking war stories. The bastard lived long enough (82?) to talk about it so ya gotta listen.
Ya got me on the Growler part tho... Only sub service has been in the
21st century ;- ) ws

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Originally Posted by Boatsb

Go Krush. great Idea. Like a light bulb came on.

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Actually, it was sorta serious comment--use potato to remove broken lightbulb...use something similar to remove broke drill bit.

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Originally Posted by yachtsmanbill

My pal gators barber was a bow gunner (anti aircraft) on the Intrepid. Old Harve doesnt mind talking war stories. The bastard lived long enough (82?) to talk about it so ya gotta listen.
Ya got me on the Growler part tho... Only sub service has been in the
21st century ;- ) ws

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I noticed some of the WWII vets are willing to speak a little bit.

One, who is father of a friend, was in the Battle of the Bulge as a tank commander. Said his turret was blown off, 2-3 men died inside, how he survived I don't know. Another said his brother had his ship sunk from under him the Atlantic, went to the Pacific...ditto! My Uncle was commander in WWII of several supply ships of the type in the Mr. Roberts movie, all documented on the internet. Found a writeup on the internet describing a major battle in which he partook, Gulf of Leyte I think. He took a destroyer under tow away from burning waters, after major attack by Japanese aircraft. Also picked up many men on fire. The destroyer sank the next day. He desribed to me being in a typhoon and other ships going be driven by huge seas and winds with men screaming for help as there ships were later to sink in the seas. My Little League coach, as nice a man as I have known, was very gaunt. Later found out he was in one of the death camps/marches and survived; I don't think he totally recovered. Our small town mayor was a German POW for several years...wrote a book now that he is in his mid 80's. My sons father-in-law was conscripted into the German Army in WWII, but was Austrian...no love lost! He escaped from a Russian front prison camp, with 3 others and they went over the Alps. He said he was the only survivor, as the others all died or were killed.

None of it a pleasant experience. I hope we don't revisit any of that in my lifetime, except we have had Vietnam, Desert Storm, and now Iragi Freedom. The scope of WWII was far more massive, but about 5x more men lost (450k+ vs 57k). Then there is the forgotten war...Korea where we lost more men than in Vietnam. Several of my personal friends were killed or maimed in Vietnam. One has the scars and a Bronze Star to show for it all.

I count my blessings. Sorry for the streaming!

Thanks for that SB... sometimes I wish I had the talent to put these stories into prose. Once these vets are gone, their tales of bravery will be lost forever!
I had an uncle that was a tank commander in the bulge and died there too, but it was 10 years before my time. He was awarded the CMH and the bronze star postumously, but better than that, my grandfather name a yacht after him, the "CHARLIE R" for Capt Charles Rose. People back then were SOOO DAMNED REAL. Unlike the plastic bastards today.
We now return control of the soapbox to you, our viewers.... ws

I have often used from a set of short shanked left-hand drill bits to get a bite on a broken bolt, trick I use is to drill a short ways with a size slightly smaller than the LH bit, then while bearing down and using a reversible drill (my ONLY drill to use is the Milwaukee right angle drill) slowly start up and while drilling in revers the flukes dig in and you can thread out the broken bolt providing its not too corroded.

That Milwaukee 3/8's angle drill is my absolute favorite.