Broken drill bit in a broken extractor in a stuck bolt... Help

hobbes · Jan 29, 2015

Recently the company i work for purchased a 1 inch extruder. We came to find out that at some point in its life it had a couple of extruder pressure disk bolts that had been cut and ground flush to the barrel. We needed to get these out. So the first attempt to remove these was to drill holes in them and try to use a hefty extractor. The drilling process went well enough. Long story short, the extractor snapped in the bolt. Fantastic. Method number 2: attempt to drill out the extractor with a harder drill bit and get a different/larger extractor whilst soaking the bold in penetrating oil for weeks on end. I was not around (honest) when my boss decided to attempt the drilling process. Using a standard right hand drill bit ( :mad5:

you can see where this is going), the bit caught the extractor locked up and snapped the drill bit. Even more fantastic. So now the situation was a broken drill bit in a broken extractor... Now the icing on the cake. Before i was able to do some research and find peoples common solution of getting a punch on the bit and bashing it with a BFH to shatter the bolt and continue to drill out with the proper LEFT hand drill bit, an attempt was made to build up some weld on the surface of the bold and then attempt to weld a nut on that surface to then wrench over the entire bolt.

So this is where we stand. We have a broken drill bit in a broken screw extractor in a stuck bolt soaking in penetrating oil with a bunch of weld covering all of that and nuts that continually shear the weld.

Any thoughts? basically any idea would be appreciated.

Thanks

WILLEO6709 · Jan 29, 2015

know anyone with a tap disintegrator? small enough to fit in a sinker edm? grind em off again and leave em?

honestly i have had success with carbide end mills cutting hss drills and taps.... ez outs... etc. My favorite way is in a vmc where I have better feed control but I have done it on the radial drill a few times.... even the bridgeport but use the knee, not the quill. It always snaps the carbide when it breaks through.... but it generally chips out if it is not evacuated with a good air blast.

SteveBausch · Jan 29, 2015

Whatever you decide, you will most likely keep your job.

I would most likely refuse to do further work on it, since I didn't mess it up, and it's a bigger mess, now.

And telling truth to power isn't a good idea.

How big is the bolt diameter?

How deep is the bolt?

I'm thinking a plasma torch might be able to melt/blow all that crap out of your way, but not knowing the bolt diameter and length will make anyone's attempt to help you simply guesswork.

EDM is nice, a tap burner is nice, but this won't fit in either, right?

hobbes · Jan 29, 2015

Cant really grind them off and leave them. It allows for too much plastic to pool inside the barrel where they enter and then you get burnt plastic and it takes forever to to get different colors running. Might know a shop with sinker EDM stuff. but at the moment the barrel is still attached to the machine. Kind of unwieldy to move around.

hobbes · Jan 29, 2015

Sadly i dont really have the option to refuse to work on this haha. Although that sounds glorious. the bolt diam is half inch. its about 1-3/4 deep. Some methods that i have thought may work, would be grind all the weld off and try to smash the bit again. but im not entirely this will work and would rather not mess it up.

cncdumm · Jan 29, 2015

another option is to weld or braze something on and thread the whole thing out.

doug8cat · Jan 29, 2015

Is that also reffered to as the "bitbroextbolt" you know like the turducken?

emcmike · Jan 29, 2015

can you drill from the opposite side and take a punch and knock it out , then put in a blank and remachine ?

ManualEd · Jan 29, 2015

When you try to weld the nut on to take the bolt out, are you pre-heating the bolt and nut to prevent cracking? If the machine its on can take it, lots of heat helps the bolts come out when you get a nut welded on there.

Another option may be a dainty oxygen lance, if its a carbon steel easy out, and there isn't much too much drill bit in the way.

hobbes · Jan 29, 2015

@cncdumm
Thats part of the current problem. it seems that much axial pressure on the weld is just shearing the weld off.

@doug8cat
Yes im certain thats what it is.

@emcmike
Not an option, this bolt runs into an ID channel and i cant get at the other side.

Also something of note. this bolt is a half inch fine thread. i dont know if that makes any difference.

WILLEO6709 · Jan 29, 2015

hobbes said:
the bolt diam is half inch. its about 1-3/4 deep. Some methods that i have thought may work, would be grind all the weld off and try to smash the bit again..

impact therapy works pretty good on carbide but on hss... I have had poor luck. What equipment do you have to work with or are you using portable tools( handheld drill motors, cordless, etc)? on a 1/2 inch bolt I'd be getting that thing clamped to a rigid machine table and go after it with a 3/8 carbide endmill at 1600 rpm.... peck slowly and keep all the chips blown out, if you hear it rumbling you have loose stuff around the cut, back it out and blow it out.. If you can get the hss thin enough you can break it with a punch and hammer but blow as big a hole as you dare in it first. Tell your boss to disassemble the machine and let you have at it with a carbide end mill in a machine

hobbes · Jan 29, 2015

@ManualEd
I have all of 0 hours welding experience so im not sure about that. but ill check in on that when i can.

@WILLEO6709
I am mostly stuck with portable tools in this case. Even if i did get the barrel off to work with, all i have is a Grizzly G1006 to work with. And i would say that it is not very rigid at all. Although i do like the sounds of that idea i dont think that i can do that here. Maybe we could send the part in to have that kind of thing done to it.

hobbes · Jan 29, 2015

This is what things look like right now

Caladin · Jan 29, 2015

This is a similar idea but rather than a nut tig a 7/16 washer to the bolt then weld a nut to the washer. This lets you get a better weld. And don't use a plated washer they won't weld on good. Can you cut in a slot and use a big flat head impact driver?

hobbes · Jan 29, 2015

I like the idea of cutting a slot. i might give that a go tomorrow.

Tonytn36 · Jan 29, 2015

Is it a left-hand thread?

crossthread · Jan 29, 2015

That's a good one hobbes. Usually when I do something like that I take a step back from the mill to keep from smashing my forehead when I bend over to grab my ankles. It's a shame they don't make a portable, small, recirculating, sand blasting device that shoots carbide grit to eat something like that out. Kind of like one of those hokey spark plug cleaners that never seem to work very good. It would take a while but sometimes slow is fine.

hobbes · Jan 29, 2015

@Tonytn36
No, its right-hand

@crossthread
I think that was my issue. I didnt step away. it causes an awful headache....

lane · Jan 29, 2015

Take it to a good machine shop they can get it out.All it takes is a vertical mill and some one that knows what he is doing. about a 1 hour job.

emcmike · Jan 29, 2015

hobbes said:
@Tonytn36
No, its right-hand

@crossthread
I think that was my issue. I didnt step away. it causes an awful headache....

and forgot someone put locktite on it , good grefffff........

Broken drill bit in a broken extractor in a stuck bolt... Help

Plastic

Diamond

Stainless

Plastic

Plastic

Cast Iron

Titanium

Hot Rolled

Stainless

Plastic

Diamond

Plastic

Plastic

Plastic

Plastic

Diamond

Titanium

Plastic

Cast Iron

Hot Rolled

Similar threads