Advice to remove snapped drill

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MikeT
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Advice to remove snapped drill

Post by MikeT »

While trying to drill out a bolt that sheared and left the stud flush in the hole, the drill snapped inside it, also shearing flush. It's a titanium drill bit and trying to drill it out with another titanium drill bit doesn't appear to work.

Is there a proven method to get out of this situation (preferred) or shall I just forget about it and try to fabricate a new bolt hole close by?
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Post by CitroJim »

That's a tricky one Mike :(

The pros would resort to spark erosion to overcome a difficulty like that. They can do it but you'd have to remove the item and take it to them and I don't believe it'll be fantastically cheap.

What is the part so afflicted? Is it a critical component?

Might be easier to replace the part wholesale...
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Post by FrenchLeave »

Hi Mike, as you've found out, like materials won't cut each other :cry: .

It's difficult to advise you without knowing the size of bolt that sheared, the size of drill that snapped and the component that the sheared bolt is in. But for what it's worth I can think of a number of possible courses of action:

A small Dramel type grinder; a fine (n0 1) oxy-acetelyne nozzle to kill the temper in the drill; a harder drill; a cold chisel applied to the periphery of the sheared bolt to try to unscrew it; as a last resort I'd knock up a trepaning tool from tool steel and trepane around the outside of the drill to give enough room to get purchase on it.

Sorry if this isn't what you're looking for, perhaps one of our experts could be more helpful.

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Post by FrenchLeave »

Sorry Jim, I was typing at the same time as you :lol:

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Post by Peter.N. »

If there is any of the bolt above the surface, weld a nut onto it, you might be able to do this even if its flush as you can weld through the centre of the nut. The heat should also loosen the bolt.
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Post by MikeT »

Sorry for the lack of detail. The bolt is one of three that fasten the underside of the bumper skirt. It's a 10mm from memory and the drill bit is 2.5mm. Although I said they snapped the flush, there was some successful drilling meaning the stud is now slightly recessed and the broken drill is also recessed. If I could weld, I doubt I'd get a purchase on it anyway.

I do have a cordless dremel type and that might be my best option but am clueless about which stone material I'd need to grind titanium.

What drill bits are harder than titanium and are they expensive?
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Post by DickieG »

Wouldn't it be easier to simply drill a second hole close by and use a new bolt or loop a cable tie around a new hole?
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Post by cachaciero »

MikeT wrote:Sorry for the lack of detail. The bolt is one of three that fasten the underside of the bumper skirt. It's a 10mm from memory and the drill bit is 2.5mm. Although I said they snapped the flush, there was some successful drilling meaning the stud is now slightly recessed and the broken drill is also recessed. If I could weld, I doubt I'd get a purchase on it anyway.

I do have a cordless dremel type and that might be my best option but am clueless about which stone material I'd need to grind titanium.

What drill bits are harder than titanium and are they expensive?
I'm reasonably sure that a "titanium" drill is in fact High Speed Steel with a titanium coating.

If you have access to a high current arc welder you could use this to either weld a stub on (stub held in electrode holder and applied to bolt) should be able to get quite a solid weld this way although you might like to practice a bit first (both halves of the weld will get red hot over much of their length!)
Or as an alternative if you have a tungsten electrode you could use this as a crude spark erosion device previous caveat applies practice on something unimportant first.

I reckon you will be wasting your time with a grinder I'm sure that there are grinding materials which will touch this although I'm not sure of what, tungsten carbide possibly? but I feel that you may use up a lot of them and I bet they won't be cheap.

Further thought may be off the wall but:----- It does occur to me that a TIG welder used without a wire but with relatively high pressure gas could be used as a super spark errosion device, the arc is drawn between the tungsten electrode and the bolt the gas is used to "blow out" the molten metal. Just a thought.

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Post by AndersDK »

Cobalt drills are even harder than titanium.
So are their pricetags ...

The problem you have now if you keep on drilling, is that your new larger & harder cobalt drillbit will constantly tend to slide sidewards and drill out the softer material in the bolt, not taking out the snapped titanium bit.

And that by itself may quickly snap your new drillbit ...

You will need a very firm support for your powerdrill and hands if you decide to continue drilling to keep it square during the job.
Do not allow the drillbit to tilt sidewards during the job. It wont flex.

Also you should try a much larger dia drillbit, at least 6mm.
The cobalt drillbit must be cooled/lubed during use.
You may use 3in1 or engine oil.
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Post by MikeT »

Thank you everyone for your helpful suggestions - it appears I don't have the facilities to try some of the options so I'll look to fabricating a new bolt hole or other fastener.
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Post by addo »

Seldom does an amateur attempt to remove a broken fastener with embedded drill, end in success. It usually culminates in a somewhat damaged hole with the remaining threaded stub, two broken drill bits and a snapped Ezy-Out added to the mixture.

I believe the bolt is broken inside a weld-on nut or cage nut. Either is pretty simple to renew.
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Post by Deanxm »

Ah, ezy outs, the most useless invention on earth, didnt they realise that if the head has sheared off that maybe the bolt in question is rather reluctant to come out? and that winding something that has all the structural properties of glass but made of the hardest steel in the universe into the stud thats left may not be the best of ideas :lol: this nube has been there before, always, always break the welder out, step away from the ezy outs!!!

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Post by steelcityuk »

As noted by others I usually go for building up the bolt with a MIG welder set on a higher than normal setting but used in very short bursts. This has been sucessful on sheared bumper bolts on the XMs rear wrap around bumper. The intense heat certainly helps.

Steve.
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